WO2025171908A1 - Testing tci state switch delay - Google Patents

Abstract

Example embodiments of the present disclosure relate to methods, devices, apparatuses and computer readable storage medium for testing transmission configuration indicator (TCI) state delay. In a method, a first apparatus transmits, to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic. The first apparatus transmits, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state. The first apparatus verifies a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus.

Description

TESTING TCI STATE SWITCH DELAY

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of IN Provisional Application No. 202441010570, filed February 15, 2024. The entire content of the above-referenced application is hereby incorporated by reference.

FIELDS

[0002] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for testing transmission configuration indicator (TCI) state delay.

BACKGROUND

[0003] Multiple-Input-Multiple-Output (MIMO) refers to the type of wireless transmission and reception scheme where both a transmitter and a receiver employ more than one antenna. MIMO allows for spatial diversity to transmit data by use of a plurality of antennas in both uplink (UL) and downlink (DL) directions. The main tool for beam indication for downlink is a Transmission Configuration Indication (TCI) framework. User equipment (UE) can be configured with a plurality of TCI states, for example up to 128 TCI states.

SUMMARY

[0004] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: transmit, to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; transmit, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state; and verify a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus. i [0005] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive, via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; receive, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state; and based on receiving the indication, start reception with the second TCI state via the first antenna.

[0006] In a third aspect of the present disclosure, there is provided a method. The method comprises: transmitting, at a first apparatus to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; transmitting, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state; and verifying a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus.

[0007] In a fourth aspect of the present disclosure, there is provided a method. The method comprises: receiving, at a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; receiving, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state; and based on receiving the indication, starting reception with the second TCI state via the first antenna.

[0008] In a fifth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for transmitting, to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; means for transmitting, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state; and means for verifying a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus.

[0009] In a sixth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for receiving, via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; means for receiving, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state; and means for based on receiving the indication, starting reception with the second TCI state via the first antenna.

[0010] In a seventh aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the third aspect or fourth aspect.

[0011] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0013] FIG. 1A illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0014] FIG. IB illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0015] FIG. 2 illustrates an example diagram of beam hierarchy;

[0016] FIG. 3 illustrates an example diagram of Quasi Co-location (QCL) and TCI chain;

[0017] FIG. 4 illustrates an example diagram of timeline of TCI state indication for Physical Downlink Shared Channel (PDSCH) in single- Downlink Control Information (s-DCI);

[0018] FIG. 5 A illustrates an example diagram of a single-to-single TCI state switch test;

[0019] FIG. 5B illustrates an example diagram of a dual-to-dual TCI state switch test;

[0020] FIG. 6 illustrates a signaling flow for testing TCI state switch delay according to some example embodiments of the present disclosure;

[0021] FIG. 7 illustrates a test setup for m-TRP according to some example embodiments of the present disclosure;

[0022] FIG. 8 illustrate an example process of testing a dual to dual TCI state switch delay according to some example embodiments of the present disclosure;

[0023] FIG. 9 illustrate another example process of testing a dual to dual TCI state switch delay according to some example embodiments of the present disclosure;

[0024] FIG. 10 illustrates a flowchart of a method implemented at a first apparatus according to some example embodiments of the present disclosure;

[0025] FIG. 11 illustrates a flowchart of a method implemented at a second apparatus according to some example embodiments of the present disclosure;

[0026] FIG. 12 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0027] FIG. 13 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0028] Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

[0029] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0030] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0031] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0032] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

[0033] As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0034] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. 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”, “comprising”, “has”, “having”, “includes” and/or “including”, when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/ or combinations thereof. [0036] As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable):

(i) a combination of analog and/or digital hardware circuit(s) with software/firmware and

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0037] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0038] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G), the sixth generation (6G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0039] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0040] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0041] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other combination of the time, frequency, space and/or code domain resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0042] Principle and implementations of the present disclosure will be described in detail below with reference to FIGS. 1-13. FIG. 1A illustrates an example communication environment 100 in which example embodiments of the present disclosure can be implemented. In the communication environment 100, a first apparatus 110 and a second apparatus 120 may communicate with each other. In some example embodiments, the first apparatus 110 may be a network device and the second apparatus 120 may be a terminal device.

[0043] In some example embodiments, in a testing case, the first apparatus 110 may be referred to as a test equipment (TE) and the second apparatus 120 may be referred to as a device under test (DUT).

[0044] An example implementation of the communication environment 100 will be described with reference to FIG. IB. FIG. IB illustrates an example communication environment 150 in which example embodiments of the present disclosure can be implemented. In the communication environment 150, a DUT 170 may be located within an anechoic chamber 190, and the DUT 170 may operate as the second apparatus 120 in FIG. 1A and a system simulator 160 may operate as the first apparatus 110 in FIG. 1A.

[0045] The communication environment 150 may further include a plurality of antennas 180-1, ..., 180-N (where N represents a positive integer). For the purpose of discussions, the plurality of antennas 180-1, ..., 180-N will be individually or collectively referred to as antenna(s) 180. The antennas 180 may also be referred to as antenna probes. In some embodiments, the antennas 180 may be a component of the system simulator 160 or separate from the system simulator 160. In either of the above cases, the system simulator 160 can control signal transmission of the antennas 180. The system simulator 160 may test TCI state switch delay of the DUT 170 via the antennas 180.

[0046] It is to be understood that the number of apparatuses and their connections shown in FIG. 1A and FIG. IB are only for the purpose of illustration without suggesting any limitation. The communication environment 100 may include any suitable number of apparatuses configured to implementing example embodiments of the present disclosure.

[0047] In the following, for purpose of illustration, some example embodiments are described with the first apparatus 110 operating as the system simulator 160 or the TE and the second apparatus 120 operating as the DUT 170. However, in some example embodiments, operations described in connection with the system simulator 160 or TE may be implemented at the DUT 170 or other device, and operations described in connection with the DUT 170 may be implemented at the system simulator 160, a TE or other devices.

[0048] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

[0049] As discussed, the main tool for beam indication for downlink is the TCI framework. The existing release (Rel)-15 new radio (NR) frequency range 2 (FR2) minimum UE requirements are defined with an assumption that UE is only required to receive with a single antenna panel at a time and capable to perform DL reception using a single receiver (RX) beam/chain. Furthermore, the UE performance requirements are limited for DL MIMO rank 1 and 2 in FR2. In FR2, 4-layer MIMO reception requires beam reception from at least two directions. Although this is supported by the MIMO features since Rel-15, no UE performance requirements have yet been specified. This is important for high-rate MIMO in FR2, as well as for FR2 high speed train (HST) scenarios.

[0050] Several enhancements to enable efficient and robust DL multi-Transmission and Receiving Point (TRP)/panel operation were introduced in the Rel-16 NR eMIMO work item (WI). However, no radio frequency (RF), radio resource management (RRM) or performance requirements were defined in Rel-16 and Rel-17 for FR2 UEs with simultaneousReceptionDiffTypeD-rl6 capability.

[0051] Enhanced NR FR2 UEs with multi -beam simultaneous reception and multiple RX chains can provide a meaningful performance improvement in FR2 improving both demodulation performance (4-layer DL MIMO), RRM performance and improve RF spherical coverage. Therefore, in Rel-18, the work item NR_FR2_multiRX_DL is being developed, which aims to introduce the requirements for UEs capable of multi -beam/chain simultaneous DL reception on a single component carrier to achieve improved RF, RRM and UE demodulation performance.

[0052] Different implementation scenarios could be considered at the UE. Single- TCI reception on different beams has been supported by the RANI specifications since Rel- 15 via the Type I codebook, which could be achieved at the UE with either a single panel or multiple panels. Alternatively, dual TCI operation can be combined with the Rel-17 mTRP framework even if the base station is actually deployed as a single TRP. This WI therefore provides the requirements for both single and dual TCI assumptions to specify requirements for reception of 4-layer downlink MIMO with simultaneous reception at the UE from two different directions.

[0053] NR cell may comprise one or multiple TRPs. TRPs of the same cell have a common Synchronization Signal (SS)/ Physical Broadcast Channel (PBCH) block which is cell specific. In Multiple Transmit/Receive Point (multi-TRP) operation, a serving cell can schedule the UE from two TRPs, providing better coverage, reliability and/or data rates for Physical Downlink Shared Channel (PDSCH), Physical Downlink Control Channel (PDCCH), Physical Uplink Shared Channel (PUSCH), and Physical Uplink Control Channel (PUCCH).

[0054] There are two different operation modes to schedule multi-TRP PDSCH transmissions: single-downlink control information (DCI) and multi-DCI. For both modes, control of uplink and downlink operation can be done by physical layer and medium access control (MAC) layer, within the configuration provided by the radio resource control (RRC) layer. In single-DCI mode, only one TRP is responsible for the transmission of control data (that is PDCCH) to the UE. As a result, the UE is scheduled by the same PDCCH containing a DCI for both TRPs. On the other hand, in multi-DCI mode two TRPs are responsible for the transmission of control data to the UE. As a result, the UE is scheduled by independent DCIs from each TRP.

[0055] Additionally, there are two different operation modes for single DCI multi-TRP PDCCH, which are PDCCH repetition and single frequency network (SFN) based PDCCH transmission. In both modes, the UE can receive two PDCCH transmissions, one from each TRP, carrying the same DCI. In a PDCCH repetition mode, the network will transmit and the UE may receive the two PDCCH transmissions carrying the same DCI from two linked search spaces each associated with a different CORESET. In an SFN based PDCCH transmission mode, the network performs and the UE may receive the two PDCCH transmissions carrying the same DCI from a single search space/CORESET using different TCI states.

[0056] The third generation partnership project (3 GPP) defined 5G NR Frequency Range 2 bands have huge bandwidths which can cater to 5G NR use cases requiring higher data rates. However, these bands are also subject to challenging propagating conditions such as high path loss, absorption from the environment, penetration losses to name a few. To overcome these, beam management procedures have been defined in 3GPP.

[0057] Beam Management is a set of procedures to assist UE to set its receive (Rx) and transmit (Tx) beams for downlink and uplink transmissions, respectively. NR supports a hierarchical beam-based approach with the synchronization signal block (SSB) beam being the root beam. FIG. 2 illustrates an example diagram 200 of beam hierarchy. As illustrated, channel state information reference signal (CSI-RS) #0 220, CSI-RS #1 230, CSI-RS #2 240 and CSI-RS #3 250 are associated to SSB #n 210.

[0058] Quasi Co-location (QCL) framework is used for beam indication. Beam indication information provided by gNB is to configure UE with information which Tx beam is to be used for DL (and UE can select proper Rx beam) and which Tx beam is to be used for UL (so that UE’s Tx is “directed” towards used RX beam at gNB).

[0059] The UE can be configured with a list of up to M TCI-State configurations within the higher layer parameter PDSCH Config to decode PDSCH according to a detected PDCCH with DCI intended for the UE and the given serving cell, where M depends on the UE capability maxNumberConfiguredTCIstatesPerCC.

[0060] Each TCI-State contains parameters for configuring a QCL relationship between one or two downlink reference signals (RS) and the demodulation (DM)-RS ports of the PDSCH, the DM-RS port of PDCCH or the CSI-RS port(s) of a CSI-RS resource. The QCL relationship is configured by the higher layer parameter qcl-Typel for the first DL RS, and qcl-Type2 for the second DL RS (if configured). For the case of two DL RSs, the QCL types shall not be the same, regardless of whether the references are to the same DL RS or different DL RSs.

[0061] The QCL types corresponding to each DL RS are given by the higher layer parameter qcl-Type in QCL-Info and may take one of the following values. QCL type A corresponds to Doppler shift, Doppler spread, average delay, delay spread. QCL type B corresponds to Doppler shift, Doppler spread. QCL type C corresponds to average delay, Doppler shift. QCL type D corresponds to Spatial Rx.

[0062] The gNB configures the UE via RRC signaling with TCI states where each TCI state may have one or two source RSs that provide QCL parameters for the target RS - only one RS providing QCL type D per TCI state. FIG. 3 illustrates an example diagram 300 of QCL and TCI chain. As illustrated, a DL TCI chain consists of an SSB, and one or more CSI-RS resources, and the TCI state of each reference signal includes another reference signal in the same TCI chain. The SSB can be associated with serving cell primary cell ID (PCID) or associated with a PCID different from serving cell PCID. The letters on the solid line or the dashed line represent respective QCL types. DMRS of PDCCH or PDSCH is QCLed with the reference signal in its active TCI state and any other reference signal that is QCLed, based on the criteria for DL TCI chain, with the reference signal in the active TCI state.

[0063] M-TRP may be deployed as multi (m)-DCI or single (s)-DCI. In case of s-DCI, the UE will have a single PDCCH and may have two PDSCH.

[0064] A single medium access control - control element (MAC-CE) will indicate two TCI states for activation. The UE maintains an active TCI state list containing codepoints. Table 1 shows codepoints in case of s-DCI.

Table 1

[0065] As shown in table 1, the UE can have up to 8 codepoints with combinations of one or two TCI states. The network then sends a DCI indicating the TCI states to be used for PDSCH reception. These TCI states will be from the active TCI state list.

[0066] RAN4 agreed to use Rel-17 group-based beam reporting as a prerequisite for multi-Rx reception in Rel-18. In group-based beam reporting the UE reports N groups/pairs (i.e. beams that can be simultaneously received) of M beams (i.e. at least 2 beams in one group). The pairing is done by the UE according to its capabilities. Rel-17 Group-Based Beam Reporting selects best beam pair from configured channel measurement resources (CMR) sets based on LI - reference signal receiving power (RSRP) measurements.

[0067] TCI state switch requirements for FR2 have currently only been defined for Rel- 15 single TRP and enhanced in Rel-16/17 to include requirement for unified TCI state framework. So far there are no RAN4 requirements for TCI state switch in case of multi- TRP. In 3GPP Rel-18, TCI state switch requirements will be defined for multi-Rx chain UEs in the multi-TRP scenario.

[0068] 3GPP defined 5G NR FR 2 bands have huge bandwidths which can cater to 5G NR use cases requiring higher data rates. However, these bands are also subject to challenging propagating conditions such as high path loss, absorption from the environment, penetration losses to name a few. To overcome these, beam management procedures have been defined in 3 GPP.

[0069] The TCI framework is used in NR and is particularly useful for beam indication in FR2 scenarios where beam management procedures are used. The requirements for TCI state active list update delay and the corresponding RRM test case are defined in RAN4 RRM requirements in 38.133 for single TRP.

[0070] There are two test cases currently defined in 38.133 Section A.7.5.8 i.e. MAC CE based active TCI state switch and RRC based active TCI state switch. In case of MAC - CE based TCI state switch test, the UE (for example, the DUT) is configured with two different TCI states each of which is QCL’d to two different SSBs. At the start of the test, the UE is indicated TCI 0 which is QCL to SSB0.

[0071] The test time period is divided into two test periods T1 and T2. During test period Tl, only SSB 0 is transmitted and UE is using TCI 0. At the beginning of test period T2, the system simulator transmits SSB 1. The UE sends Ll-RSRP report with RSRP levels of SSB 0 and SSB 1.

[0072] The system simulator sends a MAC-CE at slot n indicating that the UE should switch to TCI 1. The system simulator checks if the UE can receive via TCI 0 up to slot n+Tharq+3ms and via TCI 1 after slot n+Tharq+3ms + Tfi_rstssB+ SSB_prOc. Since this test is for FR2, it is an over the air (OTA) test.

[0073] TCI state switch RRM requirements and test have only been defined for single TRP, which may be referred to specification TS 38.133 Section A.5.7.8.

[0074] During the HST FR2 work in Rel-17, a new feature was designed for the HST UE to be able to adapt to large differences in TRP reference timing when performing TCI switching. Due to the large propagation difference in DL during beam switching for highspeed train scenarios, the legacy RRM requirements (namely, the maximum autonomous time adjustment step) defined in TS 38.133 could not be applied. As a result, the one-shot large uplink timing adjustment requirement was specified. Since the test methods corresponding to the legacy RRM requirements were not catered for such a large differential propagation delay, they could not be used to demonstrate compliance. To this end, an over-the-air test method was specified in TS 38.133 clause A.7.5.8.3 to show that the behavior of UE is complied with the one-shot large uplink timing adjustment requirement following a successful beam switch. In this method, the TE uses a single antenna array in order to emulate 2 different TRPs, and applies a different delay for the signals related to the second TRP. Once the TE sends the TCI switching command for the DUT, the TE monitors the UL transmissions to verify that the UE applied the one/shot UL timing adjustment in accordance with the emulated second TRP.

[0075] As part of the ongoing multi-Rx work item, RAN4 has defined RRM requirements for MAC-CE based switching with s-DCI which is as follows. FIG. 4 illustrates an example diagram 400 of timeline of TCI state indication for PDSCH in s- DCI. As illustrated, for s-DCI, if the dual target TCI states are known, upon receiving PDSCH carrying MAC-CE active TCI state list update from a TRP at slot n 410, UE shall be able to receive PDCCH to schedule PDSCHs from both TRPs with the new target TCI states at the first slot that is after n+ THARQ +3Nsiot^{subframe, Fl} +Tok*(max (Tfirst -SSBl , Tfirst- SSB2)+ TssB-proc) / NR slot length. In other words, the UE shall be able to be scheduled with DCI indicating the newly activated TCI state after this delay. The TCI state indicated in the DCI shall then be applied latest after delay timeDurationForQCL, where timeDurationForQCL is the time required by the UE to perform PDCCH reception and applying spatial QCL information received in DCI for PDSCH processing. For s-DCI, for dual TCI to single TCI state switch, when the target TCI is one of the source TCI (e.g. [RSI, RS2] to [RSI]), there is no TCI switching delay when UE is configured with guaranteed bit rate (GBR) and is not configured with non-GBR.

[0076] The existing Rel-15 RRM test cases for TCI state switch have been defined for s-TRP. These test cases cannot be used for verifying UE conformance to m-TRP RRM requirements especially in case of s-DCI mode of deployment.

[0077] Additionally, the m-TRP TCI state switch delay RRM requirements will apply only when the UE is configured with the parameter groupBaseBeamReporting-R17 and the UE may receive the target dual TCI states simultaneously.

[0078] The RRM test cases defined currently use two probes to verify UE single TCI state switch delay conformance for s-TRP. FIG. 5A illustrates an example diagram 500 of single-to-single TCI state switch test. As illustrated, a UE 510 may initially perform reception via TCI#0 from the antenna probe#l 520. Upon receiving a switch command, after a delay, the UE 510 may perform reception via TCI#1 from the antenna probe#2 530. [0079] In light of this, it is logical that, to test a dual-to-dual TCI state switch. FIG. 5B illustrates an example diagram 550 of dual-to-dual TCI state switch test. As illustrated, four antenna probes (i.e., the antenna probe#l 520, the antenna probe#2 530, the antenna probe#3 560, the antenna probe#4 570) would be required.

[0080] Hence, as the number of TRPs and the number of TCI states that a UE may use simultaneously grows in the future, the number of probes required in the test setup to check UE conformance requirements for TCI state switch delay will also increase which is not feasible from test equipment point of view. It will also become increasingly difficult to place the UE in the test chamber so that the UE would be able to receive from all the increasing number of probes with sufficient angular separation. The problem is how to use reduced number of antenna probes to verify UE TCI state switch delay conformance requirements.

[0081] In order to solve at least part of the above problems or other potential problems, the present disclosure provides a solution on testing TCI state delay. In the solution, a first apparatus (for example, a TE or system simulator) transmits, to a second apparatus (for example, a DUT) via a first antenna, a first reference signal corresponding to a first TCI state and a second reference signal corresponding to a second TCI state. The first and second reference signals is different in a signal characteristic. The first apparatus transmits, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state. Based on receiving the indication, the second apparatus starts reception with the second TCI state via the first antenna. In this way, whether the UE meets the TCI state switch delay RRM requirements may be verified by using a reduced number of antennas.

[0082] FIG. 6 illustrates a signaling flow 600 for testing TCI state switch delay according to some example embodiments of the present disclosure. The signaling flow 600 involves the first apparatus 110 and the second apparatus 120 in FIG. 1 A. For purpose of illustration, the signalling flow 600 will be described with respect to FIG. 1A. For purpose of discussion, some example embodiments are described where the first apparatus 110 is implemented as a TE or system simulator and the second apparatus 120 is implemented as a DUT.

[0083] In operation, the first apparatus 110 transmits (610), via a first antenna, a first reference signal corresponding to a first TCI state and a second reference signal corresponding to a second TCI state. The second apparatus 120 receives (615), via the first antenna, the first reference signal and the second reference signal. The first and second reference signals are different in a signal characteristic. The reference signal may be any suitable reference signal, for example, SSB, tracking reference signal (TRS), etc. In this way, different beams may be simulated by employing the different signal characteristics.

[0084] In some example embodiments, the signal characteristic may comprise at least one of a transmitting time offset, a signal transmit power, or a transmitting frequency offset. In other words, the different RSs from a same antenna may be differ from each other by having different transmitting time offsets, or different signal transmit powers, or different transmitting frequency offsets.

[0085] The first apparatus 110 transmits (620) an indication of a switch from the first TCI state to the second TCI state. The indication is also referred to as “switch indication” or “TCI state switch indication”. Correspondingly, the second apparatus 120 receives (625) the switch indication from the first apparatus 110. In an example, the switch indication may be included in DCI or in MAC-CE.

[0086] Thus, the first reference signal is associated with (for example, QCL-d) transmission before the switch and the second reference signal is associated with (for example, QCL-d) transmission after the switch. In some example embodiments, transmission of the first reference signal and the second reference signal may start at different times. For example, transmission of the first reference signal may be started within a first time period (such as the period T1 as described below), and transmission of the second reference signal may be started at a beginning of a second time period ((such as the period T2 as described below)) succeeding the first time period.

[0087] Based on receiving the switch indication, the second apparatus 120 performs the TCI state switch from the first TCI state to the second TCI state, and starts (630) reception with the second TCI state via the first antenna. The TCI state switch may have a delay, and the second apparatus 120 is expected to perform reception on the second TCI state at a certain time after receiving the switch indication.

[0088] The first apparatus 110 verifies (635) a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus 120. For example, the first apparatus 110 may schedule PDCCH or PDSCH transmissions with the second TCI state at a certain time after the switch indication is transmitted. Based on whether the PDCCH or PDSCH is received by the second apparatus 120, the first apparatus 110 may determine whether the switch time meets the delay requirement.

[0089] In some example embodiments, the transmission with the second TCI state may be scheduled after a time duration since transmitting the switch indication and the time duration may be used for the second apparatus 120 to receive the indication and apply QCL information. Accordingly, the reception with the second TCI state at the second apparatus 120 may be started after the time duration since receiving the switch indication. In an example, the time duration may be the parameter timedur ationforQcl, as described above.

[0090] In some example embodiments, the first apparatus 110 may transmit a message to activate the second TCI state. The second apparatus 120 may receive the message from the first apparatus 110 accordingly. The switch indication may be transmitted and/ or received after a time determined based on one or more of a time delay for TCI state activation, a time for feeding back reception of the message, a transmission time of the second reference signal (in other words, a transmission time of the reference signal associated with the target TCI state), a predetermined time duration, and a time for reference signal processing.

[0091] An example general procedure is described above. In the present disclosure, a test method is proposed to verify if the UE can meet the TCI state switch delay RRM requirements by using a reduced number of antenna probes in the test setup.

[0092] The existing test setup for TCI state switch delay conformance tests uses two antenna probes as the currently defined tests are for s-TRP where the UE at any given point in time will have a single indicated TCI state for PDSCH and/or PDCCH. The present disclosure proposes a method to use reduced number of probes for TCI state switch by emulating different spatial directions within a single probe by making artificial beams using different time offset and different transmit power. For example, the SSBs which would be related to different TRPs may be transmitted with different transmit power and/or different transmit timing from the same probe.

[0093] This test method enables efficient use of the existing test setup and can be used for the existing single to single TCI state switch in s-TRP as well can be extended to test higher number of TCI state switch delay requirements, i.e., dual to dual TCI state switch delay requirements or more.

[0094] In s-DCI, the UE may have four types of TCI state switches for PDSCH, i.e., single to single TCI state switch, single to dual TCI state switch, dual to dual TCI state switch and dual to single TCI state switch. The test method may be applied to these four types of TCI state switches.

[0095] As an example without any limitation, the following will describe an example of testing a delay in a dual-to-dual TCI state switch.

[0096] In some example embodiments, the switch indication may further indicate a switch from a third TCI state to a fourth TCI state. This means that the switch indication indicates the second apparatus 120 of a dual-to-dual TCI state switch.

[0097] In these example embodiments, as shown in FIG. 6, the first apparatus 110 may transmit (640), via a second antenna, a third reference signal corresponding to the third TCI state and a fourth reference signal corresponding to the fourth TCI state. The second apparatus 120 may receive (645), via the second antenna, the third reference signal and fourth reference signal.

[0098] Based on receiving the switch indication, the second apparatus 120 may perform the TCI state switch from the third TCI state to the fourth TCI state, and start (650) reception with the fourth TCI state via the second antenna. The TCI state switch may have a delay, and the second apparatus 120 may be expected to perform reception on the fourth TCI state at a certain time after receiving the switch indication.

[0099] The first apparatus 110 may verify (655) a switch time of the switch from the third TCI state to the fourth TCI state by scheduling, via the second antenna, transmission with the fourth TCI state to the second apparatus 120. For example, the first apparatus 110 may schedule PDCCH or PDSCH transmissions with the second TCI state at a certain time after the switch indication is transmitted. Based on whether the PDCCH or PDSCH is received by the second apparatus 120, the first apparatus 110 may determine whether the switch time from the third TCI state to the fourth TCI state meets the delay requirement.

[0100] Similar as described above with reference to the first and second reference signals, in some example embodiments, transmission of the third reference signal and the fourth reference signal may start at different times. For example, transmission of the third reference signal may be started within the first time period (such as the period T1 as described below), and transmission of the fourth reference signal may be started at a beginning of the second time period ((such as the period T2 as described below)) succeeding the first time period.

[0101] In some example embodiments, the second apparatus 120 may configured to perform group-based beam reporting. For example, the second apparatus 120 may transmit a measurement report for at least one reference signal group. The first apparatus 110 may receive the measurement report. The reference signal groups may include a group including the first reference signal and the third reference signal, a group including the first reference signal and the fourth reference signal, a group including the second reference signal and the third reference signal, or a group including the second reference signal and the fourth reference signal.

[0102] To better understand the embodiments of the present disclosure, example test setup and testing process are now described.

[0103] The RRM conformance tests for s-TRP are carried out using two antenna probes. The test setup for m-TRP may be described with reference to FIG. 7, which illustrates a test setup for m-TRP according to some example embodiments of the present disclosure. As illustrated, the same setup (two antenna probes, i.e., PROBE #1 520 and PROBE #2 530) may be used for verifying UE conformance in case of a m-TRP setup.

[0104] In this example, the probe 1 may transmit SSB#0 and SSB#1 while the probe 2 may transmit SSB#2 and SSB#3. In this setup, the probe 1 and probe 2 may emulate two different DL transmit beams. Probe 1 may emulate a first DL transmit beam (that is the beam before TCI state switch) by transmitting SSB#0 and all the signals that are QCL-D with SSB#0 with a delay (as an example of the transmitting time offset) dO and a power offset (as an example of the signal transmit power) APO. Probe 1 may emulate a second downlink transmit beam (that is the beam after TCI state switch) by transmitting SSB#1 and all the signals that are QCL-D with SSB#1 with a delay dl, and a power offset API.

[0105] Probe 2 may emulate a first DL transmit beam (that is the beam before TCI state switch) by transmitting SSB#2 and all the signals that are QCL-D with SSB#2 with a delay d2 and a power offset AP2. Probe 2 may emulate a second downlink transmit beam by transmitting SSB#3 and all the signals that are QCL-D with SSB#3 with a delay d3 and a power offset AP3. [0106] It is to be noted that the difference between the delays dx and dy should not exceed the maximum receive time difference requirements. In Multi Rx Rel 18, this limit is equal to the cyclic-prefix (CP) length.

[0107] In some example embodiments, d0=d2=0 and AP0=AP2=0 for the first emulated downlink transmit beam of probe 1 and probe 2. In some example embodiments, APO, API, AP2, AP3 = 0.

[0108] This test setup can be used for testing RRM test cases like TCI state switch delay. For example, a dual TCI state to dual switch delay test case is described below using this setup.

[0109] In the initial configuration stage, a DUT (as an example of the second apparatus 120) may be configured with 5 different TCI states. For PDCCH, the DUT may be configured with TCI# 0 (QCL’d to SSB0). For PDSCH, the DUT may be configured with TCI#1 (QCL’d to SSB1), TCI#2 (QCL’d to SSB2), TCI#3 (QCL’d to SSB3) and TCI#4 (QCL’d to SSB0). It is to be noted that the proposed solution assumes Rel-15 TCI states, where TCI states are separate for PDCCH and PDSCH. Alternatively, if unified TCI states are used, there is no need for separate PDCCH TCI state (TCI#0 in this example), as the TCI states are common for PDCCH and PDSCH.

[0110] Alternatively, or in addition, the parameter tci-PresentlnDCI may be configured, and the DUT is configured with groupBaseBeamReporting-R17. Group based beam reporting may be configured for the UE to report 4 groups, with CRM group 1 (SSB0 and SSB1) and CRM group 2 (SSB2 and SSB3). The DUT may be initially indicated to use TCI#4 as the active TCI state for PDCCH, and TCI#0 and TCI#2 for PDSCH.

[0111] FIG. 8 illustrate an example process 800 of testing a dual to dual TCI state switch delay according to some example embodiments of the present disclosure. As illustrated, a UE (as an example of the second apparatus 120) may initially receive from TCI states (as an example of the first TCI state and the third TCI state) QCL’d to SSB#0 840 and SSB#2 842. At time 810, the UE may receive DCI for TCI state switch (as an example of the indication of the switch from the first TCI state to the second TCI state or from the third TCI state to the fourth TCI state). After the time duration timedurationforQCL 820, the UE may receive from target TCI states (as an example of the second TCI state and the fourth TCI state) QCL’d to SSB#1 844 and SSB#3 846. [0112] FIG. 9 illustrate another example process 900 of testing a dual to dual TCI state switch delay according to some example embodiments of the present disclosure. As illustrated, the test period may consist of test periods T1 910 (as an example of first time period) and T2 920 (as an example of second time period). During test period T1 910, SSB# 0 840 (as an example of the first reference signal), SSB#2 842 (as an example of the third reference signal) to which the source TCI states, PDCCH TCI#0 913, PDSCH TCI#4 914, PDSCH TCI#2 915, are QCL’d, may be transmitted.

[0113] At the beginning of test period T2 920, SSB#1 844 (as an example of the second reference signal) and SSB#3 846 (as an example of the fourth reference signal) starts transmitting. At time 930, the DUT (as an example of the second apparatus 120) may be configured to provide periodic group based Ll-RSRP reports. The DUT may be expected to perform the group based beam reporting with groups as follow: SSB#0 840 plus SSB#2 842, SSB#0 840 plus SSB#3 846, SSB#1 844 plus SSB#2 842 and SSB#1 844 plus SSB#3 846.

[0114] It is to be assumed that in slot n 935 which is within 1280ms of the DUT providing Ll-RSRP of SSB#0 840, SSB#1 844, SSB#2 842 and SSB#3 846, the DUT may receive a MAC-CE command for activation of a codepoint containing the states TCI#1 916 and TCI#3 917 (as an example of the message to activate the second TCI state). It is to be noted that at this moment the DUT is already receiving PDCCH on TCI#4 914 and PDSCH on TCI#0 913 and TCI#2 915.

[0115] After a time that corresponds (at least) to TCI state activation delay n+ THARQ (as an example of the time for feeding back reception of the message) + 3ms (as an example of the predetermined time duration) + max (Tfirst-ssm, Tfi_rst-ssB3) (as an example of the transmission time of the second reference signal associated with the target TCI states) + TssB-proc (as an example of the time for reference signal processing), the system simulator (as an example of the first apparatus 110) may send a DCI indicating switch to TCI states TCI#1 916 and TCI#3 917. THARQ is the timing between DL data transmission and acknowledgement. Tfi_rst-ssBi is time to first SSB#1 transmission after MAC CE command is decoded by the UE. Tfi_rst-ssB3 is time to first SSB#3 transmission after MAC CE command is decoded by the UE. TssB-proc is the time to process the SSB.

[0116] Then, the system simulator may verify the TCI state switch delay by scheduling the UE on TCI#1 916 and TCI#3 917 (at least) timedurationforQcl after sending the DCI, i.e., at n+ THARQ +3ms + max (Tfirst-ssBi, Tfi_rst-ssB3) + TssB-proc + timedurationforQcl after sending the MAC-CE.

[0117] If the transmission time of the SSB#1 844 and SSB#3 846 is earlier than the next SSB#0 840 and SSB#2 842, the max(Tfi_rst-ssBi, Tfi_rst-ssB3) will be lesser than max (Tfirst- SSBO, Tfirst-ssB2) and hence if the DUT can receive from TCI#1 916 and TCI#3 917 at n+ THARQ +3ms + max(Tfirst-ssBi, Tfi_rst-ssB3)+ TssB-proc + timedurationforQcl, then it can be confirmed that the DUT conforms to the TCI state switch delay requirements for m-TRP as specified in RAN4.

[0118] This test methodology may also be used for single-to-single TCI state switch delay conformance tests by activating and indicating only a single TCI state with MAC- CE and DCI for PDSCH, or it can also be used for indicating a single TCI state for PDCCH through MAC-CE, where the corresponding single TCI state switching delay requirement would be verified. Similarly, the test methodology can be further extended to support higher number of TCI state switch delay tests.

[0119] Furthermore, the results of the spherical coverage tests may be used to find the best usable test points for the UE for this test. In addition to a time offset, a frequency offset can be added to SSB#1 844 and SSB#3 846 as compared to SSB#0 840 and SSB#2 842 respectively.

[0120] FIG. 10 shows a flowchart of an example method 1000 implemented at a first device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of the first apparatus 110 in FIG. 1A.

[0121] At block 1010, the first apparatus 110 transmits, to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic.

[0122] At blockl020, the first apparatus 110 transmits, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state.

[0123] At block 1030, the first apparatus 110 verifies a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus. [0124] In some example embodiments, the signal characteristic comprises at least one of: a transmitting time offset, a signal transmit power, or a transmitting frequency offset.

[0125] In some example embodiments, the transmission with the second TCI state is scheduled after a time duration since transmitting the indication, the time duration being used for the second apparatus to receive the indication and apply quasi co-location (QCL) information.

[0126] In some example embodiments, the method 1000 further comprises: transmitting, to the second apparatus, a message to activate the second TCI state, wherein the indication is transmitted after a time determined based on one or more of: a time delay for TCI state activation, a time for feeding back reception of the message, a transmission time of the second reference signal, a predetermined time duration, and a time for reference signal processing.

[0127] In some example embodiments, the method 1000 further comprises: transmitting, to the second apparatus via a second antenna, a third reference signal corresponding to the third TCI state and a fourth reference signal corresponding to the fourth TCI state; and verifying a switch time of the switch from the third TCI state to the fourth TCI state by scheduling, via the second antenna, transmission with the fourth TCI state to the second apparatus.

[0128] In some example embodiments, the method 1000 further comprises: receiving, from the second apparatus, a measurement report for at least one reference signal group of: a group including the first reference signal and the third reference signal, a group including the first reference signal and the fourth reference signal, a group including the second reference signal and the third reference signal, or a group including the second reference signal and the fourth reference signal.

[0129] In some example embodiments, transmission of the first reference signal is started within a first time period, and transmission of the second reference signal is started at a beginning of a second time period succeeding the first time period.

[0130] In some example embodiments, the first apparatus comprises a test equipment, and the second apparatus comprises a device under test.

[0131] FIG. 11 shows a flowchart of an example method 1100 implemented at a second device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1100 will be described from the perspective of the second apparatus 120 in FIG. 1A.

[0132] At block 1110, the second apparatus 120 receives, via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic.

[0133] At block 1120, the second apparatus 120 receives, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state.

[0134] At block 1130, based on receiving the indication, the second apparatus 120 starts reception with the second TCI state via the first antenna.

[0135] In some example embodiments, the signal characteristic comprises at least one of a transmitting time offset, a signal transmit power, or a transmitting frequency offset.

[0136] In some example embodiments, the reception with the second TCI state is started after a time duration since receiving the indication, the time duration being used for the second apparatus to receive the indication and apply QCL information.

[0137] In some example embodiments, the method 1100 further comprises: receiving, from the first apparatus, a message to activate the second TCI state, wherein the indication is received after a time determined based on one or more of a time delay for TCI state activation, a time for feeding back reception of the message, a transmission time of the second reference signal, a predetermined time duration, and a time for reference signal processing.

[0138] In some example embodiments, the method 1100 further comprises: receiving, via a second antenna, a third reference signal corresponding to the third TCI state and a fourth reference signal corresponding to the fourth TCI state; and based on receiving the indication, starting reception with the fourth TCI state via the second antenna.

[0139] In some example embodiments, the method 1100 further comprises: transmitting, to the first apparatus, a measurement report for at least one reference signal group of: a group including the first reference signal and the third reference signal, a group including the first reference signal and the fourth reference signal, a group including the second reference signal and the third reference signal, or a group including the second reference signal and the fourth reference signal. [0140] In some example embodiments, reception of the first reference signal is started within a first time period, and reception of the second reference signal is started at a beginning of a second time period succeeding the first time period.

[0141] In some example embodiments, the first apparatus comprises a test equipment, and the second apparatus comprises a device under test.

[0142] In some example embodiments, a first apparatus capable of performing any of the method 1000 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1A.

[0143] In some example embodiments, the first apparatus comprises means for transmitting, to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; means for transmitting, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state; and means for verifying a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus.

[0144] In some example embodiments, the signal characteristic comprises at least one of a transmitting time offset, a signal transmit power, or a transmitting frequency offset.

[0145] In some example embodiments, the transmission with the second TCI state is scheduled after a time duration since transmitting the indication, the time duration being used for the second apparatus to receive the indication and apply quasi co-location (QCL) information.

[0146] In some example embodiments, the first apparatus further comprises: means for transmitting, to the second apparatus, a message to activate the second TCI state, wherein the indication is transmitted after a time determined based on one or more of a time delay for TCI state activation, a time for feeding back reception of the message, a transmission time of the second reference signal, a predetermined time duration, and a time for reference signal processing.

[0147] In some example embodiments, the indication further indicates a switch from a third TCI state to a fourth TCI state, the first apparatus further comprises: means for transmitting, to the second apparatus via a second antenna, a third reference signal corresponding to the third TCI state and a fourth reference signal corresponding to the fourth TCI state; and means for verifying a switch time of the switch from the third TCI state to the fourth TCI state by scheduling, via the second antenna, transmission with the fourth TCI state to the second apparatus.

[0148] In some example embodiments, the first apparatus further comprises: means for receiving, from the second apparatus, a measurement report for at least one reference signal group of: a group including the first reference signal and the third reference signal, a group including the first reference signal and the fourth reference signal, a group including the second reference signal and the third reference signal, or a group including the second reference signal and the fourth reference signal.

[0149] In some example embodiments, transmission of the first reference signal is started within a first time period, and transmission of the second reference signal is started at a beginning of a second time period succeeding the first time period.

[0150] In some example embodiments, the first apparatus comprises a test equipment, and the second apparatus comprises a device under test.

[0151] In some example embodiments, the first apparatus further comprises means for performing other operations in some example embodiments of the method 1000 or the first apparatus 110. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the performance of the first apparatus.

[0152] In some example embodiments, a second apparatus capable of performing any of the method 1100 (for example, the second apparatus 120 in FIG. 1A) may comprise means for performing the respective operations of the method 1100. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1A.

[0153] In some example embodiments, the second apparatus comprises means for receiving, via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; means for receiving, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state; and means for based on receiving the indication, starting reception with the second TCI state via the first antenna.

[0154] In some example embodiments, the signal characteristic comprises at least one of a transmitting time offset, a signal transmit power, or a transmitting frequency offset.

[0155] In some example embodiments, the reception with the second TCI state is started after a time duration since receiving the indication, the time duration being used for the second apparatus to receive the indication and apply QCL information.

[0156] In some example embodiments, the second apparatus further comprises: means for receiving, from the first apparatus, a message to activate the second TCI state, wherein the indication is received after a time determined based on one or more of a time delay for TCI state activation, a time for feeding back reception of the message, a transmission time of the second reference signal, a predetermined time duration, and a time for reference signal processing.

[0157] In some example embodiments, the indication further indicates a switch from a third TCI state to a fourth TCI state, the second apparatus further comprises: means for receiving, via a second antenna, a third reference signal corresponding to the third TCI state and a fourth reference signal corresponding to the fourth TCI state; and means for based on receiving the indication, starting reception with the fourth TCI state via the second antenna.

[0158] In some example embodiments, the second apparatus further comprises: means for transmitting, to the first apparatus, a measurement report for at least one reference signal group of: a group including the first reference signal and the third reference signal, a group including the first reference signal and the fourth reference signal, a group including the second reference signal and the third reference signal, or a group including the second reference signal and the fourth reference signal.

[0159] In some example embodiments, reception of the first reference signal is started within a first time period, and reception of the second reference signal is started at a beginning of a second time period succeeding the first time period.

[0160] In some example embodiments, the first apparatus comprises a test equipment, and the second apparatus comprises a device under test.

[0161] In some example embodiments, the second apparatus further comprises means for performing other operations in some example embodiments of the method 1100 or the second apparatus 120. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the performance of the second apparatus.

[0162] FIG. 12 is a simplified block diagram of a device 1200 that is suitable for implementing example embodiments of the present disclosure. The device 1200 may be provided to implement a communication device, for example, the first apparatus 110 or the second apparatus 120 as shown in FIG. 1. As shown, the device 1200 includes one or more processors 1210, one or more memories 1220 coupled to the processor 1210, and one or more communication modules 1240 coupled to the processor 1210.

[0163] The communication module 1240 is for bidirectional communications. The communication module 1240 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 1240 may include at least one antenna.

[0164] The processor 1210 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1200 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0165] The memory 1220 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1224, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1222 and other volatile memories that will not last in the power-down duration.

[0166] A computer program 1230 includes computer executable instructions that are executed by the associated processor 1210. The instructions of the program 1230 may include instructions for performing operations/acts of some example embodiments of the present disclosure. The program 1230 may be stored in the memory, e.g., the ROM 1224. The processor 1210 may perform any suitable actions and processing by loading the program 1230 into the RAM 1222.

[0167] The example embodiments of the present disclosure may be implemented by means of the program 1230 so that the device 1200 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 9. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0168] In some example embodiments, the program 1230 may be tangibly contained in a computer readable medium which may be included in the device 1200 (such as in the memory 1220) or other storage devices that are accessible by the device 1200. The device 1200 may load the program 1230 from the computer readable medium to the RAM 1222 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0169] FIG. 13 shows an example of the computer readable medium 1300 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1300 has the program 1230 stored thereon.

[0170] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0171] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non- transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0172] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0173] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0174] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0175] Further, although operations are depicted 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 certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0176] Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: transmit, to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; transmit, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state; and verify a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus.

2. The first apparatus of claim 1, wherein the signal characteristic comprises at least one of: a transmitting time offset, a signal transmit power, or a transmitting frequency offset.

3. The first apparatus of claim 1, wherein the transmission with the second TCI state is scheduled after a time duration since transmitting the indication, the time duration being used for the second apparatus to receive the indication and apply quasi co-location (QCL) information.

4. The first apparatus of claim 1, wherein the first apparatus is further caused to: transmit, to the second apparatus, a message to activate the second TCI state, wherein the indication is transmitted after a time determined based on one or more of: a time delay for TCI state activation, a time for feeding back reception of the message, a transmission time of the second reference signal, a predetermined time duration, and a time for reference signal processing.

5. The first apparatus of claim 1, wherein the indication further indicates a switch from a third TCI state to a fourth TCI state, and the first apparatus is further caused to: transmit, to the second apparatus via a second antenna, a third reference signal corresponding to the third TCI state and a fourth reference signal corresponding to the fourth TCI state; and verify a switch time of the switch from the third TCI state to the fourth TCI state by scheduling, via the second antenna, transmission with the fourth TCI state to the second apparatus.

6. The first apparatus of claim 5, wherein the first apparatus is further caused to: receive, from the second apparatus, a measurement report for at least one reference signal group of: a group including the first reference signal and the third reference signal, a group including the first reference signal and the fourth reference signal, a group including the second reference signal and the third reference signal, or a group including the second reference signal and the fourth reference signal.

7. The first apparatus of claim 1, wherein transmission of the first reference signal is started within a first time period, and transmission of the second reference signal is started at a beginning of a second time period succeeding the first time period.

8. The first apparatus of claim 1, wherein the first apparatus comprises a test equipment, and the second apparatus comprises a device under test.

9. A second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive, via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; receive, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state; and based on receiving the indication, start reception with the second TCI state via the first antenna.

10. The second apparatus of claim 9, wherein the signal characteristic comprises at least one of: a transmitting time offset, a signal transmit power, or a transmitting frequency offset.

11. The second apparatus of claim 9, wherein the reception with the second TCI state is started after a time duration since receiving the indication, the time duration being used for the second apparatus to receive the indication and apply QCL information.

12. The second apparatus of claim 9, wherein the second apparatus is further caused to: receive, from the first apparatus, a message to activate the second TCI state, wherein the indication is received after a time determined based on one or more of: a time delay for TCI state activation, a time for feeding back reception of the message, a transmission time of the second reference signal, a predetermined time duration, and a time for reference signal processing.

13. The second apparatus of claim 9, wherein the indication further indicates a switch from a third TCI state to a fourth TCI state, and the second apparatus is further caused to: receive, via a second antenna, a third reference signal corresponding to the third TCI state and a fourth reference signal corresponding to the fourth TCI state; and based on receiving the indication, start reception with the fourth TCI state via the second antenna.

14. The second apparatus of claim 13, wherein the second apparatus is further caused to: transmit, to the first apparatus, a measurement report for at least one reference signal group of: a group including the first reference signal and the third reference signal, a group including the first reference signal and the fourth reference signal, a group including the second reference signal and the third reference signal, or a group including the second reference signal and the fourth reference signal.

15. The second apparatus of claim 9, wherein reception of the first reference signal is started within a first time period, and reception of the second reference signal is started at a beginning of a second time period succeeding the first time period.

16. The second apparatus of claim 9, wherein the first apparatus comprises a test equipment, and the second apparatus comprises a device under test.

17. A method comprising: transmitting, at a first apparatus to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; transmitting, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state; and verifying a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus.

18. A method comprising: receiving, at a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; receiving, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state; and based on receiving the indication, starting reception with the second TCI state via the first antenna.

19. A first apparatus comprising: means for transmitting, to a second apparatus via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; means for transmitting, to the second apparatus, an indication of a switch from the first TCI state to the second TCI state; and means for verifying a switch time of the switch from the first TCI state to the second TCI state by scheduling, via the first antenna, transmission with the second TCI state to the second apparatus.

20. A second apparatus comprising: means for receiving, via a first antenna, a first reference signal corresponding to a first transmission configuration indicator, TCI, state and a second reference signal corresponding to a second TCI state, the first and second reference signals being different in a signal characteristic; means for receiving, from the first apparatus, an indication of a switch from the first TCI state to the second TCI state; and means for based on receiving the indication, starting reception with the second TCI state via the first antenna.

21. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of claim 17 or the method of claim 18.