WO2022240339A1

WO2022240339A1 - Conditional tci state switch procedure

Info

Publication number: WO2022240339A1
Application number: PCT/SE2022/050453
Authority: WO
Inventors: Ming Li; Joakim Axmon; Muhammad Ali Kazmi; Thomas Chapman
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-05-11
Filing date: 2022-05-09
Publication date: 2022-11-17

Abstract

A method, system and apparatus are disclosed. According to one embodiment, a method implemented in a WD is provided. The WD is configured to communicate with a network node, and is further configured with at least a first and a second TCI state. The first TCI state is the currently active TCI state. The method comprises receiving (S1310) an indication from the network node to switch from the first TCI state to the second TCI state; determining (S1320)whether a condition for the switch from the first TCI state to the second TCI state is met; and in response to the received indication to switch, performing (S1330) the switch to the second TCI state when determining that the condition for the switch is met, and refraining from performing (S1340) the switch to the second TCI state otherwise.Publication:

Description

TITLE: CONDITIONAL TCI STATE SWITCH PROCEDURE

TECHNICAL FIELD

[0001] The present disclosure relates to wireless communications, and in particular, to methods implemented in a Wireless Device (WD) and in a network node for criteria/ion based Transmission Configuration Indication (TCI) state switching and to a corresponding WD and network node apparatus.

BACKGROUND

[0002] During Third Generation Projection Project (3 GPP) Release 16, 3 GPP RAN4 created Radio Frequency (RF) and Radio Resource Management (RRM) requirements for operation of New Radio (NR) for High Speed Trains (HST) in Frequency Range 1 (FR1). The specification of FR1 HST followed the specification of Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRA) HST. During 3GPP Release 17, 3GPP approved a RAN4 Work Item for the development of specifications for RF, RRM and demodulation enabling serving HSTs using FR2, and in particular the bands around 28GHz. FR1 and FR2 differ in that the frequencies in FR1 are lower than those in FR2. For example, FR1 may include frequencies between 400 MHz to 7 GHz, and FR2 may include frequencies between 24 GHz and 52.6 GHz. In another example, FR2 may include frequencies between 24 GHz and 71 GHz. In yet another example, FR2 may include frequencies at least from 24 GHz and above.

[0003] For HST operation, network nodes (e.g., base stations or Remote Radio Heads (RRH) of a base station) are typically placed along the HST track at certain intervals. For FR2, Wireless Devices (WD) are assumed to be devices fixed to the roof of the train, which further provides service to users inside the train. RRM algorithms are specified such that the network is aware of the network node(s) which are best placed to serve the WDs, and operates TCI state change or handover between the network nodes as the train moves along the track.

1 [0004] An example of two deployment parameters is illustrated in FIG. 1 and Table 1.

Ds is the distance between two RRHs.

Dmin is the straight-line distance from RRH to rail track.

[0005] Scenario A and Scenario B are defined as corresponding to different values of Dmin, while Ds is the same in both scenarios.

[0006] TABLE 1

[0007] In FR2, two types of deployments have been considered. They are referred to as a uni directional deployment, and a bi-directional deployment.

[0008] In uni-directional deployment, the antennas or beams from all network nodes point in the same direction along the track. In FR2, also the WDs may need to maintain good enough beamforming gain on the receiver side for receiving the RRHs’ signals. Here SSB-1 and SSB-2 are Synchronization Signal (SS) and physical broadcast channel (PBCH) Block (SSB) reference signals from RRH1, and SSB-3 and SSB-4 are SSB reference signals from RRH2, as illustrated in FIG. 2.

[0009] FIG. 3 is a diagram illustrating an example of the bi-direction deployment and operation in HST FR2. In the bi-directional deployment, network nodes are located along the track with antennas or beams pointing in both directions. Network nodes may transmit towards WDs in both directions. Unlike FR1, the signals do not combine over the air as in a Single Frequency Network (SFN). This is due to the fact that the WD may have to use different panels to point different beams in each direction. Furthermore, if a WD only can transmit and receive from one

2 panel at a time, the WD must switch panels and directions, e.g. using Dynamic Point Selection (DPS), depending on which direction instantaneously has better signal quality.

[0010] Transmission Configuration Indication (TCI)

[0011] A WD is configured by the network node with one active TCI state for channel reception, e.g., for reception of Physical Downlink Control CHannel (PDCCH) and Physical Downlink Shared CHannel (PDSCH), respectively. The active TCI state indicates, for each of the channels, a timing reference that the WD assumes for the downlink (DL) reception. The timing reference is defined with respect to a certain DL Reference Signal (RS). Examples of RSs are SSB, Channel State Information RS (CSI-RS), Demodulation RS (DM-RS), and Positioning RS (PRS). The timing reference may for example be with respect to an SSB index associated with a particular transmit beam, or with respect to a CSI-RS resource configured by the network node and provided (i.e., transmitted) to the wireless device. Therefore, a TCI state is associated with an RS such as SSB, or CSI-RS. A TCI state is further associated with a beam since the RS may also be transmitted in the form of a beam as further described in sections herein.

[0012] The DL RS (e.g., SSB, CSI-RS) may interchangeably be referred to as a DL beam, a spatial filter, a spatial domain transmission filter, or a main lobe of the radiation pattern of an antenna array. The active TCI state additionally indicates to the WD which WD receive (RX) beam to use when receiving PDCCH and/or PDSCH, since the WD uses the WD RX beam that allows best conditions for receiving the SSB index or DL-RS resource associated with the TCI state. The best WD RX beam of a given TCI state may change over time, for example, if the WD orientation changes. However, the best WD RX beam also has to be relatively static, i.e. static at least over shorter time intervals.

3 [0013] Up to 8 TCI states can be configured for PDSCH via higher layer signaling (Radio Resource Control (RRC) signaling), but only one TCI state can be active at a time. The active TCI state is used by the WD for receiving the channels, e.g., PDCCH and PDSCH. In case several TCI states are configured by the network node, the network node indicates to the WD via Downlink Control Indication (DCI) on PDCCH which one of the pre-configured TCI states to activate for upcoming PDSCH reception(s).

[0014] The active TCI state can be switched by the WD based on a command received from the network in a Media Access Control (MAC), DCI or RRC message. This is referred to as active TCI state switching. Upon receiving a TCI state switch command, the WD first sends Hybrid Automatic Repeat Request (HARQ) feedback to the serving cell and switches to a target active TCI state within a certain delay.

[0015] The target TCI state can be known or unknown to the WD at the time of activation of the TCI state, i.e. at the time of receiving the TCI state switch command.

[0016] The target TCI state is known if the following conditions are met:

During the period from the last transmission of the RS resource used for a Layer 1 Reference Signal Received Power (Ll-RSRP) measurement reporting for the target TCI state to the completion of the active TCI state switch, where the RS resource for Ll- RSRP measurement is the RS of the target TCI state or is quasi-co-located (QCLed) to the RS of the target TCI state: o The TCI state switch command is received within 1280 ms of the last transmission of the RS resource for beam or measurement reporting;

4 o The WD has sent at least one Ll-RSRP report for the target TCI state before the

TCI state switch command; o The target TCI state remains detectable during the TCI state switching period; o The RS (e.g., SSB) associated with the target TCI state remains detectable during the TCI switching period;

^■ SNR of the target TCI state > -3dB.

[0017] Otherwise, the target TCI state is unknown.

[0018] The RS or beams comprising RSs may be addressed or configured by an identifier, which can indicate the location of the beam in time in the beam pattern, e.g., beam index such as SSB index indicate SSB beam location in the pre-defined SSB format/pattern.

[0019] Ll-RSRP is a measurement in NR for Beam Management (BM). BM is also interchangeably referred to as a link recover procedure. The WD may send Ll-RSRP reports only for report configurations configured for the active Bandwidth Part (BWP).

[0020] Table 2 - Measurement period TLi-R_SRP_M_{ea urement}_P_eriod_ssB for FR2

[0021] Since Ll-RSRP is used for BM in the serving cell, and given the high speed at which the WD is moving, it is desirable that the latency in Ll-RSRP measurement is kept low such that

5 measured values filtered over the measurement period as much as possible reflect the current signal conditions.

[0022] How TCI state switching is impacted by the Ll-RSRP measurement period, TDRX, and TSSB, and how this in turn impacts the Signal to Noise Ratio (SNR) in the received signals is described below.

[0023] First example: scenario B + uni-directional deployment [0024] With reference to FIG. 4:

The upper left panel illustrates the ideal SNR as varying along the rail track.

The upper right panel illustrates SNR when a Ll-RSRP periodicity with 3 times 40ms TSSB/DRX is used.

The lower left panel illustrates SNR when a Ll-RSRP periodicity with 3 times 80ms TSSB/DRX is used.

The lower right panel illustrates SNR when a Ll-RSRP periodicity with 3 times 160ms TSSB/DRX is used.

[0025] Second example: scenario B + bi-directional deployment [0026] With reference to FIG. 5:

The upper left panel illustrates the ideal SNR as varying along the rail track.

The lower left panel illustrates SNR when a Ll-RSRP periodicity with 3 times 80ms

TSSB/DRX is used.

6 The lower right panel illustrates SNR when a Ll-RSRP periodicity with 3 times 160ms

TSSB/DRX is used.

[0027] The panels with ideal SNR are just used as a reference. From a practical point of view, analysis focuses on the other panels with non-ideal SNR:

The curve “N” demonstrates the best SNR after LI -filtering. This can be interpreted as beam switching with no delay.

For the other curve “Y”, a certain beam switch delay due to Ll-RSRP measurement is taken into account.

[0028] For either of the first or the second example, it can be seen in Figures 4 and 5 that the Ll- RSRP measurement delay may cause SNR to drop when the WD is moving into a target RRF s beam after passing the source RRH. The SNR drop is generally worse with longer TSSB/DRX periodicity. There is thus a need to improve performance at TCI state switching in certain scenarios.

SUMMARY

[0029] Some embodiments advantageously provide methods, systems, and apparatuses for criteria/ion based TCI state switching.

[0030] According to a first aspect, a method implemented in a WD is provided. The WD is configured to communicate with a network node, and is further configured with at least a first and a second TCI state. The first TCI state is the currently active TCI state. The method comprises receiving an indication from the network node to switch from the first TCI state to the second TCI state; determining whether a condition for the switch from the first TCI state to the second TCI state is met; and in response to the received indication to switch, performing the

7 switch to the second TCI state when determining that the condition for the switch is met, and refraining from performing the switch to the second TCI state otherwise.

[0031] According to a second aspect, a method implemented in a network node that is configured to communicate with a WD configured with at least a first and a second TCI state is provided. The first TCI state is the currently active TCI state. The method comprises transmitting an indication to the WD to switch from the first TCI state to the second TCI state. The WD determines whether to switch from the first TCI state to the second TCI state depending on whether a condition is met..

[0032] According to further aspects, a WD and a network node configured to perform the methods according to the first and the second aspects are provided. Corresponding non-transitory computer-readable mediums and computer program products are also provided.

[0033] Advantages of embodiments described herein are that they provide a flexible and dynamic TCI state switching mechanism that maintains stable SNR despite aspects such as high speed of a train in the case of HST and rapidly changing beam conditions. Stable SNR is an advantage both for mobility and connectivity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

• FIG. 1 is a diagram of RRH placements in a HST scenario;

• FIG. 2 is a diagram of uni-directional operation in HST FR2;

FIG. 3 is a diagram of bi-directional operation in HST FR2;

8 • FIG. 4 show diagrams illustrating measured SNR level along the rail track in four different cases of a first example scenario;

• FIG. 5 show diagrams illustrating measured SNR level along the rail track in four different cases of a second example scenario;

• FIG. 6 is a schematic diagram of an exemplary network architecture illustrating a communication system connected via an intermediate network to a host computer according to the principles in the present disclosure;

• FIG. 7 is a block diagram of a host computer communicating via a network node with a WD over an at least partially wireless connection according to some embodiments of the present disclosure;

• FIG. 8 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a WD for executing a client application at a WD according to some embodiments of the present disclosure;

• FIG. 9 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a WD for receiving user data at a WD according to some embodiments of the present disclosure;

• FIG. 10 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a WD for receiving user data from the WD at a host computer according to some embodiments of the present disclosure;

• FIG. 11 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a WD for receiving user data at a host computer according to some embodiments of the present disclosure;

9 FIG. 12a-b are flowcharts of exemplary processes in a network node according to some embodiments of the present disclosure;

• FIG. 13a-b are flowcharts of exemplary processes in a WD according to some embodiments of the present disclosure;

• FIG. 14 is a diagram illustrating a bi-directional deployment according to some embodiments of the present disclosure;

• FIG. 15 is a diagram illustrating a uni-directional deployment according to some embodiments of the present disclosure;

• FIG. 16 is a signaling diagram of a first embodiment according to some embodiments of the present disclosure;

• FIG. 17 is a signaling diagram of a second embodiment according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

[0035] Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to criterion based TCI state switching. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

[0036] According to embodiments, the WD is configured to perform a TCI state switching, e.g., from the current active TCI state to a target TCI state. The WD will, based on a received

10 command (e.g., in a DCI, MAC-CE, or RRC message), check one or more conditions or criteria for deciding whether to switch the active TCI state. The WD does TCI state switching to a target TCI state or beam when the one or more conditions are met, otherwise the WD does not perform the TCI state switching. The WD may further be configured with one or more conditions or criteria which the WD is required to evaluate. The one or more conditions or criteria may be pre defined. The WD may further be configured with a scenario under which the WD is required to evaluate the one or more conditions or criteria. Examples of such scenarios are: when the WD is in a high speed scenario, when the WD is configured with a high speed flag, when the target TCI state is unknown, when the target TCI state or beam’s signal level is below a certain threshold (e.g., Signal to Interference and Noise Ratio (SINR) below -3 dB, or Ll-RSRP measurement below a certain threshold), or when the WD speed is above a threshold. An example of a criterion includes comparing the signal level (e.g., Ll-RSRP) of the target TCI state or beam with a certain threshold. Other examples of criteria include comparing the signal level (e.g., Ll- RSRP) of the target TCI state or beam with a certain threshold and also comparing the signal level (e.g., Ll-RSRP) of the serving active TCI state or beam with another threshold. A further type of criteria includes using position information of the WD along the track. The position information could be provided by a positioning system (e.g., a Global Positioning System (GPS)), by information provided to the WD from the train, or by an estimation based on a train speed and an elapsed time.

[0037] The WD may in embodiments also send an indication to the network node indicating whether TCI state switching to the target TCI state was performed. Based on the received indication, the network node can determine if the active TCI state was updated/switched or not. This allows the network node to start scheduling PDSCH on the new active TCI when the active

11 TCI state is updated, and to continue scheduling PDSCH on the currently active TCI state when the TCI state switch has not been performed.

[0038] Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 6 a schematic diagram of a communication system 10, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and/or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first WD (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16.

[0039] Also, it is contemplated that a WD 22 can be in simultaneous communication and/or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an

12 example, WD 22 can be in communication with an eNB for LTE/E-UTRAN and a gNB for NR/NG-RAN.

[0040] The communication system 10 may itself be connected to a host computer 24, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 24 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 26, 28 between the communication system 10 and the host computer 24 may extend directly from the core network 14 to the host computer 24 or may extend via an optional intermediate network 30. The intermediate network 30 may be one of, or a combination of more than one of, a public, private or hosted network. The intermediate network 30, if any, may be a backbone network or the Internet. In some embodiments, the intermediate network 30 may comprise two or more sub networks (not shown).

[0041] The communication system of FIG. 6 as a whole enables connectivity between one of the connected WDs 22a, 22b and the host computer 24. The connectivity may be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a, 22b are configured to communicate data and/or signaling via the OTT connection, using the access network 12, the core network 14, any intermediate network 30 and possible further infrastructure (not shown) as intermediaries. The OTT connection may be transparent in the sense that at least some of the participating communication devices through which the OTT connection passes are unaware of routing of UL and DL communications. For example, a network node 16 may not or need not be informed about the past routing of an incoming DF communication with data originating from a host computer 24 to be forwarded (e.g., handed over) to a connected WD 22a.

13 Similarly, the network node 16 need not be aware of the future routing of an outgoing UL communication originating from the WD 22a towards the host computer 24.

[0042] A network node 16 is configured to include a TCI unit 32 which is configured to perform one or more network node 16 function as described herein such as with respect to criterion or condition based TCI state switching.

[0043] A WD 22 is configured to include a state unit 34 which is configured to perform one or more WD 22 functions as described herein such as with respect to criterion based TCI state switching.

[0044] Example implementations, in accordance with an embodiment, of the WD 22, network node 16 and host computer 24 discussed in the preceding paragraphs will now be described with reference to FIG. 7. In a communication system 10, a host computer 24 comprises hardware (HW) 38 including a communication interface 40 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 10. The host computer 24 further comprises processing circuitry 42, which may have storage and/or processing capabilities. The processing circuitry 42 may include a processor 44 and memory 46. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 42 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 44 may be configured to access (e.g., write to and/or read from) memory 46, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM

14 (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read- Only Memory).

[0045] Processing circuitry 42 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by host computer 24. Processor 44 corresponds to one or more processors 44 for performing host computer 24 functions described herein. The host computer 24 includes memory 46 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 48 and/or the host application 50 may include instructions that, when executed by the processor 44 and/or processing circuitry 42, causes the processor 44 and/or processing circuitry 42 to perform the processes described herein with respect to host computer 24. The instructions may be software associated with the host computer 24.

[0046] The software 48 may be executable by the processing circuitry 42. The software 48 includes a host application 50. The host application 50 may be operable to provide a service to a remote user, such as a WD 22 connecting via an OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the remote user, the host application 50 may provide user data which is transmitted using the OTT connection 52. The “user data” may be data and information described herein as implementing the described functionality. In one embodiment, the host computer 24 may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry 42 of the host computer 24 may enable the host computer 24 to observe, monitor, control, transmit to and/or receive from the network node 16 and or the WD 22. The processing circuitry 42 of the host computer 24 may include an information unit 54

15 configured to enable the service provider to store, analyze, determine, forward, relay, transmit, receive, etc., information related to criterion based TCI state switching.

[0047] The communication system 10 further includes a network node 16 provided in a communication system 10 and including hardware 58 enabling it to communicate with the host computer 24 and with the WD 22. The hardware 58 may include a communication interface 60 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 10, as well as a radio interface 62 for setting up and maintaining at least a wireless connection 64 with a WD 22 located in a coverage area 18 served by the network node 16. The radio interface 62 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers. The communication interface 60 may be configured to facilitate a connection 66 to the host computer 24. The connection 66 may be direct or it may pass through a core network 14 of the communication system 10 and/or through one or more intermediate networks 30 outside the communication system 10.

[0048] In the embodiment shown, the hardware 58 of the network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 68 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and/or read from) the memory 72, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache

16 and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

[0049] Thus, the network node 16 further has software 74 stored internally in, for example, memory 72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 74 may be executable by the processing circuitry 68. The processing circuitry 68 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by network node 16. Processor 70 corresponds to one or more processors 70 for performing network node 16 functions described herein. The memory 72 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and/or processing circuitry 68, causes the processor 70 and/or processing circuitry 68 to perform the processes described herein with respect to network node 16. For example, processing circuitry 68 of the network node 16 may include TCI unit 32 configured to perform one or more network node 16 functions as described herein such as with respect to criterion based TCI state switching.

[0050] The communication system 10 further includes the WD 22 already referred to. The WD 22 may have hardware 80 that may include a radio interface 82 configured to set up and maintain a wireless connection 64 with a network node 16 serving a coverage area 18 in which the WD 22 is currently located. The radio interface 82 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

[0051] The hardware 80 of the WD 22 further includes processing circuitry 84. The processing circuitry 84 may include a processor 86 and memory 88. In particular, in addition to or instead of

17 a processor, such as a central processing unit, and memory, the processing circuitry 84 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 86 may be configured to access (e.g., write to and/or read from) memory 88, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

[0052] Thus, the WD 22 may further comprise software 90, which is stored in, for example, memory 88 at the WD 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22. The software 90 may be executable by the processing circuitry 84. The software 90 may include a client application 92. The client application 92 may be operable to provide a service to a human or non-human user via the WD 22, with the support of the host computer 24. In the host computer 24, an executing host application 50 may communicate with the executing client application 92 via the OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the user, the client application 92 may receive request data from the host application 50 and provide user data in response to the request data. The OTT connection 52 may transfer both the request data and the user data. The client application 92 may interact with the user to generate the user data that it provides.

[0053] The processing circuitry 84 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD 22. The processor 86 corresponds to one or more processors 86 for performing WD 22

18 functions described herein. The WD 22 includes memory 88 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 90 and/or the client application 92 may include instructions that, when executed by the processor 86 and/or processing circuitry 84, causes the processor 86 and/or processing circuitry 84 to perform the processes described herein with respect to WD 22. For example, the processing circuitry 84 of the WD 22 may include a state unit 34 configured to perform one or more WD 22 functions as described herein such as with respect to criterion based TCI state switching.

[0054] In some embodiments, the inner workings of the network node 16, WD 22, and host computer 24 may be as shown in FIG. 7 and independently, the surrounding network topology may be that of FIG. 6.

[0055] In FIG. 7, the OTT connection 52 has been drawn abstractly to illustrate the communication between the host computer 24 and the WD 22 via the network node 16, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the WD 22 or from the service provider operating the host computer 24, or both. While the OTT connection 52 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

[0056] The wireless connection 64 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the WD 22 using the OTT connection 52, in which the wireless connection 64 may form the last segment.

19 More precisely, the teachings of some of these embodiments may improve the data rate, latency, and/or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc.

[0057] In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 52 between the host computer 24 and WD 22, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 52 may be implemented in the software 48 of the host computer 24 or in the software 90 of the WD 22, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 52 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 48, 90 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 52 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the network node 16, and it may be unknown or imperceptible to the network node 16. Some such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary WD signaling facilitating the host computer’s 24 measurements of throughput, propagation times, latency and the like. In some embodiments, the measurements may be implemented in that the software 48,

90 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 52 while it monitors propagation times, errors, etc.

20 [0058] Thus, in some embodiments, the host computer 24 includes processing circuitry 42 configured to provide user data and a communication interface 40 that is configured to forward the user data to a cellular network for transmission to the WD 22. In some embodiments, the cellular network also includes the network node 16 with a radio interface 62. In some embodiments, the network node 16 is configured to, and/or the network node’s 16 processing circuitry 68 is configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/supporting/ending a transmission to the WD 22, and/or preparing/terminating/maintaining/supporting/ending in receipt of a transmission from the WD 22

[0059] In some embodiments, the host computer 24 includes processing circuitry 42 and a communication interface 40 that is configured to a communication interface 40 configured to receive user data originating from a transmission from a WD 22 to a network node 16. In some embodiments, the WD 22 is configured to, and/or comprises a radio interface 82 and/or processing circuitry 84 configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/supporting/ending a transmission to the network node 16, and/or preparing/terminating/maintaining/supporting/ending in receipt of a transmission from the network node 16.

[0060] Although FIGS. 6 and 7 show various “units” such as TCI unit 32, and state unit 34 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

21 [0061] FIG. 8 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIGS. 6 and 7, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIG. 7. In a first step of the method, the host computer 24 provides user data (Block SI 00). In an optional substep of the first step, the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50 (Block SI 02). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block SI 04). In an optional third step, the network node 16 transmits to the WD 22 the user data which was carried in the transmission that the host computer 24 initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block SI 06). In an optional fourth step, the WD 22 executes a client application, such as, for example, the client application 92, associated with the host application 50 executed by the host computer 24 (Block SI 08).

[0062] FIG. 9 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIG. 6, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 6 and 7. In a first step of the method, the host computer 24 provides user data (Block SI 10). In an optional substep (not shown) the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50. In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block SI 12). The transmission may pass via the network node 16, in accordance with the teachings of the embodiments described throughout this

22 disclosure. In an optional third step, the WD 22 receives the user data carried in the transmission (Block SI 14).

[0063] FIG. 10 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIG. 6, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 6 and 7. In an optional first step of the method, the WD 22 receives input data provided by the host computer 24 (Block SI 16). In an optional substep of the first step, the WD 22 executes the client application 92, which provides the user data in reaction to the received input data provided by the host computer 24 (Block SI 18). Additionally or alternatively, in an optional second step, the WD 22 provides user data (Block SI 20). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application 92 (Block SI 22). In providing the user data, the executed client application 92 may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD 22 may initiate, in an optional third substep, transmission of the user data to the host computer 24 (Block SI 24). In a fourth step of the method, the host computer 24 receives the user data transmitted from the WD 22, in accordance with the teachings of the embodiments described throughout this disclosure (Block SI 26).

[0064] FIG. 11 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIG. 6, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 6 and 7. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout

23 this disclosure, the network node 16 receives user data from the WD 22 (Block SI 28). In an optional second step, the network node 16 initiates transmission of the received user data to the host computer 24 (Block SI 30). In a third step, the host computer 24 receives the user data carried in the transmission initiated by the network node 16 (Block SI 32).

[0065] In one example embodiment, a network node 16 (e.g., gNB) before sending TCI state switching command to WD 22, is configured to assess or evaluate one or more conditions or criteria. The network node 16 sends the TCI state switching command for WD 22 to switch to a target TCI state provided that the conditions are met for that target TCI state. Otherwise network node 16 does not send the command to WD 22 for switching to that target TCI state, as is further described herein.

[0066] FIG. 12a is a flowchart of an exemplary process in the network node 16 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 68 (including the TCI unit 32), processor 70, radio interface 62 and/or communication interface 60. Network node 16 is configured to cause (Block SI 34) transmission of a command associated with switching the WD 22 from a first TCI state to a second TCI state where the switching is based at least on at least one signal measurement associated with the first TCI state meeting at least one predefined criterion, as described herein. Network node 16 is configured to cause (Block SI 36) transmission of signaling based at least on the second TCI state, as described herein.

[0067] According to one or more embodiments, the processing circuitry 68 is further configured to: receive measurement information associated with the at least one signal measurement, and determine whether the at least one signal measurement meets the at least one predefined criterion

24 where the transmission of signaling based on at least the second TCI state being based on determining that the at least one signal measurement meets the at least one predefined criterion. According to one or more embodiments, the command is configured to cause the WD 22 to determine whether at least one signal measurement performed by the WD 22 meets the at least one predefined criterion. The processing circuitry 68 is further configured to receive an indication that the WD 22 has switched to the second TCI state where the indication is based at least on the determination performed by the WD 22, where the causing of transmission of signaling based at least on the second TCI state is based on the received indication.

[0068] According to one or more embodiments, the at least one predefined criterion includes at least one of: comparing a signal level of a target beam to a first threshold, comparing a signal level of a source beam to a second threshold, comparing the signal level of the source beam to the signal level of the target beam, comparing a WD location to a predefined location threshold, and comparing a WD trajectory to the predefined location threshold.

[0069] In an example where WD 22 performs the TCI state switching (as further described herein), WD 22 upon receiving the TCI state switching command, assesses or evaluates one or more conditions or criteria and based on the assessment of the one or more conditions or criteria WD 22 performs or executes one or more operations or tasks. An example is as follows: if the one or more conditions are met then the operation performed by WD 22 includes performing the TCI state switching; otherwise (if conditions are not met) the operation performed by WD 22 comprising not performing the TCI state switching. WD 22 may further inform network node 16 the results of the operations performed by WD 22, e.g., indicating whether the TCI state switching is performed or not. In one specific example, WD 22 may inform only when the TCI state switching is performed. In another specific

25 example, WD 22 may inform only when the TCI state switching is not performed by WD 22

[0070] In one example, regardless of the signal levels of the target TCI state, WD 22 assesses or evaluates one or more conditions and based on the assessment of the one or more conditions,

WD 22 performs or executes one or more operations or tasks as described in the above examples.

[0071] In another example, depending on the signal levels of the target TCI state, WD 22 assesses or evaluates one or more conditions and based on the assessment of the one or more conditions, WD 22 performs or executes one or more operations or tasks as described in the above examples. For example, WD 22 evaluates the one or more conditions only if the target beam is unknown to WD 22. The target TCI state is unknown for example if the SINR of the beam associated with the TCI state is below -3 dB, the associated beam has not been measured by WD 22 over the last 1280 ms, etc.

[0072] The one or more conditions or criteria/ion can be pre-defined or they can be configured by network node 16.

[0073] Some general or generic examples of conditions are:

In one general example of the condition, only the signal level of a target beam (e.g., associated with target TCI state) is compared with a threshold (HI).

In another general example of the condition, the signal level of a target beam (e.g., associated with target TCI state) is compared with a threshold (HI) and also the signal level of a source / current beam (e.g., associated with the current active TCI state) is compared with another threshold (H2).

26 In another general example of the condition, the signal level (St) of a target beam is compared to the signal level (Ss) of a source beam, e.g., whether St is above Ss or not, whether St is above Ss by certain margin or not, etc.

In another general example, at least one of St, HI, Ss, H2, H3, H4 are evaluated together with an assessment of WD 22 position PI. WD 22 position may be assessed by, e.g., GPS, information provided from the train or a knowledge of the train speed and time since a last known WD 22 position.

[0074] Another set of non-limiting examples of conditions are expressed by the following expressions, where each expression corresponds to one condition or criteria denoted by ‘CgX’:

Cgl = fl(St, HI) (1)

Cg2 = fl(St, Ss, 51) (2)

Cg3 = fl(St, Ss, H2, 52) (3)

Cg4 = f2(St, H3, Ss, H4) (4)

Cg5 = f3([Cgl, Cg2, Cg3, Cg4], PI) (5)

[0075] Where:

In (1), the signal level (St) (e.g., Ll-RSRP) of target beam is compared with a threshold (HI).

In (2), St is compared with signal level (Ss) (e.g., Ll-RSRP) of source beam and signal offset (51) related to Ss.

In (3), St is compared with threshold (HI) and also with Ss and signal offset (52) related to Ss.

27 In (4), St is compared with threshold (H3) and Ss is compared with another threshold (H4).

In (5), the decision is made based on one of the previous 4 conditions plus an indication or estimate of WD 22 position (PI).

[0076] Some specific non-limiting examples of conditions (e.g., Cl, C2, C3, C4 and C5) or criteria are:

Cl= 'target beam signal level (St) > thresholdl' OR 'target beam signal level (St) > (source beam signal level (Ss) +/-offsetl)'

C2='target beam signal level (St) > threshold2'

C3= 'target beam signal level (St) > (source beam signal level (Ss) +/-offset2)'

C4= 'target beam signal level (St) > threshold3' AND 'target beam signal level (St) > (source beam signal level (Ss) +/-offset3)'

C5= 'target beam signal level (St) > threshold4' AND 'source beam signal level (Ss) < thresholds'

C6= WD 22 position PI within the range Px <= PI <= Py [0077] Where,

Target beam power and source beam power are Ll-RSRP from different RRH as illustrated in FIG. 14. FIG. 15 is a diagram associated with conditions including source RRH and target RRH Ll-RSRP with uni-directional deployment.

28 offsetl, offset2 and offset3, threshold!, threshold2, thresholds, threshold4 and thresholds are predefined values which can be adaptively modified according to network deployment.

The term offset may also be referred to as “margin.”

Px, Py are determined or set based on knowledge of the deployment.

Signal level refers to a measurement performed by WD 22 on RS, e.g., on SSB, CSI-RS, etc. Signal level may also be called as signal measurement. Examples of signal level are signal strength, signal quality, etc. Examples of signal strength are Ll-RSRP, path loss, etc. Examples of signal quality are Ll-RSRQ, Ll-SINR, etc.

The term source beam may also be called as serving beam, current beam, etc. The source beam is the beam of RS transmitted by the serving network node 16, e.g., serving RRH. The target beam is the beam of RS transmitted by the target network node 16, e.g., target RRH.

[0078] When WD 22 is moving and changing to target RRH from source RRH, the methods of one or mor embodiments described herein enable WD 22 to maintain stable signal conditions (e.g., no or small variation in signal quality, e.g., SNR). This is realized by performing the TCI state switching when one or more conditions or criteria are met, as described herein.

[0079] FIG. 13a is a flowchart of an exemplary process in a WD 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of WD 22 such as by one or more of processing circuitry 84 (including the state unit 34), processor 86, radio interface 82 and/or communication interface 60. WD 22 is configured to receive (Block SI 38) a command associated with switching the WD 22 from a first

29 transmission configuration indication, TCI, state to a second TCI state, as described herein. WD 22 is configured to perform (Block SI 40) at least one signal measurement associated with a first TCI state, as described herein. WD 22 is configured to perform (Block SI 42) switching to the second TCI state where the switching is based at least on the at least one signal measurement of the WD 22 meeting at least one predefined criterion, as described herein. WD 22 is configured to receive (Block SI 44) signaling based at least on the switching to the second TCI state, as described herein.

[0080] According to one or more embodiments, the processing circuitry 84 is further configured to: determine whether the at least one signal measurement meets the at least one predefined criterion where the switching is based at least on the determination that the at least one signal measurement meets the at least one predefined criterion, and cause transmission of an indication that the WD 22 has switched to the second TCI state.

[0081] According to one or more embodiments, the processing circuitry 84 is further configured to: transmit measurement information associated with the at least one signal measurement to allow the network node to determine whether the at least one signal measurement meets the at least one predefined criterion where the receiving of signaling based at least on the switching to the second TCI state is based on that determination that the at least one signal measurement meets the at least one predefined criterion.

[0082] Having generally described arrangements for criteria/ion based TCI state switching, details for these arrangements, functions and processes are provided herein, and which may be implemented by the network node 16, WD 22 and/or host computer 24.

[0083] Some embodiments provide criteria/ion based TCI state switching as described herein. One or more network node 16 functions described herein may be performed by at least one of

30 processing circuitry 68, processor 70, TCI unit 32, radio interface 62, etc. One or more WD 22 functions described herein may be performed by at least one of processing circuitry 84, processor 86, state unit 34, radio interface 82, etc.

[0084] First Embodiment: network node 16 assessing conditions for TCI state switching (see e.g. FIG. 12a and FIG. 16)

[0085] FIG. 16 is a signaling diagram associated with the network node 16 assessing condition for TCI state switching according to some examples of the present disclosure. WD 22 is configured to measure the signals of the source beam, e.g., Ll-RSRP measured on SSB of the serving beam. In one or more embodiments, the frequency of performing measurements may be periodic, aperiodic, “regularly” according to a predefined configuration, etc. WD 22 may also be configured to measure the signals of one or more target beams or beams other than the serving beams, e.g., Ll-RSRP measured on SSB of other beams. WD 22 may have to first detect a beam if WD 22 has not yet measured the beam. After the beam is detected, then WD 22 can for example periodically measure the beam, e.g., Ll-RSRP. The serving beam is measured on RS transmitted by the serving RRH. For example, WD 22 may also measure on other beams conditionally, e.g., when serving beam’s signal level fall below certain threshold or when WD 22 detects serving beam has failed, e.g., BLER is above certain threshold (e.g., 10%). detects source beam and target beam or at least between two RRHs and reports the results to network node 16 (e.g., via Ll-RSRP reporting).

[0086] WD 22 therefore measures source signals of the beam and at least target beam and reports the measured results to network node 16 (e.g., via Ll-RSRP reporting). The network node (e.g., serving BS, serving RRH, etc.) uses the received measurement results of at least the target beam to evaluate whether one or more conditions are fulfilled. And based on evaluation

31 network node 16 decides whether to send a TCI state activation command to WD 22, to perform the TCI state switching from the source TCI state to the target TCI state.

[0087] For example, assume that network node 16 uses the following criterion to decide if the TCI state should be change or not.

'target beam signal level > threshold2'

[0088] In one example, if the received result (e.g., Ll-RSRP = -75 dBm) for certain target beam (B2) is above threshold2 (e.g., -80 dBm) then network node 16 sends a TCI state switching command requesting WD 22 to switch to the target TCI state associated with the target beam,

B2. On the other hand, if the Ll-RSRP of B2 is for example -85 dBm (i.e., below threshold2) then network node 16 does not send TCI state switching command to WD 22 (at least WD 22 is not requested to change its current TCI state to TCI state associated with beam, B2). In another example, the network (e.g., network node 16) additional takes into account an indicated or estimated WD 22 position. WD 22 position may be estimated by the network (e.g., network node 16) itself or indicated from WD 22, or may be provided to the network by other control information within the railway system.

[0089] Second Embodiment: WD 22 assessing conditions for TCI state switching (see e.g. FIG. 13a, FIG. 13b, FIG.12b, and FIG. 17)

[0090] FIG. 17 is a signaling diagram associated with WD 22 assessing conditions for TCI state switching according to some examples of the present disclosure. In the legacy procedure, WD 22 performs the TCI state switching upon receiving the command from network node 16 without evaluating any condition. However, in this embodiment, WD 22 upon receiving the TCI state switching command from network node 16 further evaluates one or more conditions or criteria,

32 and based on the evaluation WD 22 decides whether to perform the TCI state switching to the target TCI state or not. WD 22 may further determine whether WD 22 is required to evaluate one or more conditions or not, for deciding whether to do TCI state switching or not. The determination can be based on an indication received from network node 16 or based on a pre defined rule. In one example, network node 16 may explicitly indicate that WD 22 is required to evaluate one or more conditions, which may be pre-defined or configured by network node 16. The indication can be sent to WD 22 in the same command as for the TCI state switching, or it can be sent in a separate message to WD 22. In another example, WD 22 may be implicitly indicated to evaluate one or more conditions. For example, if WD 22 is configured with a high speed flag, then WD 22 may be required to evaluate one or more conditions, otherwise WD 22 is not required to evaluate one or more conditions. WD 22 is configured with high speed flag when WD 22 is operating in a cell (e.g., served by a cell) supporting high speed operation, e.g., serving wireless devices 22 in high speed train. Examples of pre-defined rules are: WD 22 is required to evaluate one or more conditions if WD 22 speed is above certain or predefined threshold (e.g., above 100 km/hour), if WD 22 Doppler frequency is above certain or predefined threshold (e.g., above 800 Hz), if the target TCI state is unknown to WD 22, if the signal level of the beam associated with the target TCI state is below certain threshold (e.g., SNR is below -3 dB, Ll- RSRP is below certain threshold etc.), etc.

[0091] If based on the evaluation of one or more conditions, WD 22 determines that WD 22 meets the one or more conditions, then WD 22 performs the TCI state switching, i.e., switches the current active TCI state to the target TCI state. Otherwise, WD 22 does not perform the TCI state switching. To perform the TCI state switching, WD 22 may measure the beam associated with the target TCI state and sends the measurement result (e.g., Ll-RSRP) of the beam of the

33 target TCI state to network node 16. The TCI state switching procedure involves delay, e.g., active TCI state switching time period or delay.

[0092] The procedure described herein further elaborated on with an example. Assume that WD 22 is currently served by active TCI state associated with beam #1 (Bl) and is configured by network node 16 to perform a TCI state switch to target TCI state which is associated with a beam (B3). For example, RSI and RS3 correspond to Bl and B3, respectively. In one example, RSI and RS3 are SSBs with SSB index 1 (SSB1) and SSB index 3 (SSB3) respectively. The measured values (e.g., Ll-RSRP) of beams Bl and B3 are RSRPl and RSRP3, respectively. WD 22 is further configured to evaluate the following condition or criteria:

'target beam signal level > threshold4' AND 'source beam signal level < thresholds'

[0093] As an example: threshold4 and thresholds are -80 dBm and -75 dBm respectively:

In one example, where RSRPl = -90 dBm and RSRP3 = -75 dBm, WD 22 meets the above condition. In this case, WD 22 performs the active TCI state switching from Bl to B3, i.e., its new active TCI state after the switching becomes TCI state associated with B3.

In another example, where RSRPl = -80 dBm and RSRP3 = -90 dBm, WD 22 does not meet the above condition. In this case, WD 22 does not perform the active TCI state switching, i.e., its active TCI state remains as Bl.

[0094] WD 22 may also additionally send an indication to network node 16 whether TCI state switch to a target TCI state is performed by WD 22 or not. Based on that, network node 16 can determine if TCI state was switched by WD 22 or not. If the TCI state was switched by WD 22 (as determined by network node 16, e.g., based on indication from WD 22) then network node 16

34 may start scheduling the channels (e.g., PDSCH, PDCCH, etc.) on the new active TCI state of WD 22. But if the TCI state was not switched by WD 22 then network node 16 may continue scheduling the channels (e.g., PDSCH, PDCCH, etc.) on the current active TCI state of WD 22, i.e., the one being used by WD 22 until network node 16 sends the TCI state switching command.

[0095] One example scenario relevant for this procedure is an HST environment where the trajectory is almost fixed and the position between RRH and WD 22 can be predicted based on trajectory and WD 22 position. For example, the travel path of a WD 22 may be relative fixed (within a tolerance) as user of WD 22 is on a train/moving vehicle that follows a fixed path. Therefore, network node 16 can identify appropriate TCI state for WD 22 when changing RRH. However, due to higher speed radio conditions that change rapidly this leads to fast fluctuation in the signal quality, e.g., SINR changes. Therefore, it may be beneficial for WD 22 to check/evaluate or further check/evaluate the one or more conditions to decide whether to switch the TCI state or not. Alternatively, the known or projected WD 22 position can constitute one of the conditions.

[0096] The second embodiment may provide one or more benefits especially when the target beam is unknown compared with the first embodiment. For the first embodiment, when target beam is unknown and because network node 16 needs to check the conditions, after detecting the unknown beam then WD 22 performs the TCI state switch.

[0097] For an unknown target beam, WD 22 may perform the TCI state switch to unknown target beam only when condition(s) are met in the second embodiment. The second embodiment helps shorten the delay when target beam is unknown.

35 [0098] Accordingly, one or more embodiments of the present disclosure relate to the TCI update mechanism in e.g. HST deployment, where the difference to non-HST TCI update is that network node 16 or WD 22 checks one or more conditions that are related to the HST deployment.

[0099] FIG. 12b and 13b are flowcharts of exemplary processes in a network node 16 and WD 22 respectively according to the second embodiment of the present disclosure.

[00100] FIG. 13b is a flowchart illustrating the second embodiment of a method implemented in a WD configured to communicate with a network node. The WD is further configured with at least a first and a second TCI state, wherein the first TCI state is the currently active TCI state. The currently active TCI state may be associated with a downlink reference signal and is used to determine a receiving beam for receiving a downlink channel. The method comprises:

• S1310: Receiving an indication from the network node to switch from the first TCI state to the second TCI state. The indication to switch may be a command received in one of: a Medium Access Control message, a Radio Resource Control message, and a Downlink Control Information message

• SI 320: Determining whether a condition for the switch from the first TCI state to the second TCI state is met. The determining whether the condition is met, may comprise at least one of: determining whether a signal level of a target beam meets a first threshold (HI); determining whether a signal level of a serving beam meets a second threshold (H2); and determining whether a comparison of the signal level of the serving beam (Ss) to the signal level of the target beam (St) meets the condition. In another embodiment, the determining whether the condition is met may be based on a position of the WD (PI).

36 SI 330: In response to the received indication to switch, performing the switch to the second TCI state when determining that the condition for the switch is met;

• S1340: Refraining from performing the switch to the second TCI state otherwise, i.e., when determining that the condition for the switch is not met.

• S1350 (Optional): Indicating to the network node whether the switch to the second TCI state is performed. Indicating, S1350, may comprise transmitting information indicating: that the switch to the second TCI state is performed; or that the switch to the second TCI state is not performed.

[00101] In embodiments, the method may further comprise receiving configuration information from the network node configuring at least one of: a condition-based TCI state switch procedure; the condition; and how to determine that the condition is met.

[00102] FIG. 12b is a flowchart illustrating the second embodiment of a method implemented in a network node that is configured to communicate with a WD configured with at least a first and a second TCI state. The first TCI state is the currently active TCI state. The method comprises:

• S1410: Transmitting an indication to the WD to switch from the first TCI state to the second TCI state, wherein the WD determines whether to switch from the first TCI state to the second TCI state depending on whether a condition is met.

• SI 420 (Optional): Receiving an indication from the WD indicating whether the switch to the second TCI state is performed in response to the transmitted indication. Receiving the indication may comprise one of: receiving information indicating that the switch to the

37 second TCI state is performed; or receiving information indicating that the switch to the second TCI state is not performed.

• SI 430 (Optional): Scheduling a downlink channel on the second TCI state when the switch to the second TCI state is performed, and scheduling the downlink channel on the first TCI state when the switch is not performed.

[00103] In embodiments, the method may further comprise transmitting configuration information to the WD configuring at least one of: a condition-based TCI state switch procedure; the condition; how to determine that the condition is met.

[00104] According to embodiments, a WD configured to communicate with a network node, and further configured with at least a first and a second TCI state is provided. The first TCI state is the currently active TCI state. The currently active TCI state may be associated with a downlink reference signal and may be used to determine a receiving beam for receiving a downlink channel. The WD may be configured to receive an indication from the network node to switch from the first TCI state to the second TCI state; determine whether a condition for the switch from the first TCI state to the second TCI state is met; and in response to the received indication to switch, perform the switch to the second TCI state when determining that the condition for the switch is met, and refrain from performing the switch to the second TCI state otherwise. The WD may be further configured to indicate to the network node whether the switch to the second TCI state is performed. In embodiments, the WD may be further configured to indicate by being configured to transmit information indicating one of: that the switch to the second TCI state is performed; or that the switch to the second TCI state is not performed.

[00105] In embodiments, the WD may be further configured to receive configuration information from the network node configuring at least one of: a condition-based TCI state

38 switch procedure; the condition; how to determine that the condition is met. The WD may be further configured to receive the indication to switch in a command in one of: a Medium Access Control message, a Radio Resource Control message, and a Downlink Control Information message. The WD may be configured to determine whether the condition is met by being configured to determine at least one of: whether a signal level of a target beam meets a first threshold (HI); whether a signal level of a serving beam meets a second threshold (H2); whether a comparison of the signal level of the serving beam (Ss) to the signal level of the target beam (St) meets the condition. In embodiments, the WD may be further configured to determine whether the condition is met based on a position of the WD (PI).

[00106] According to embodiments, a network node configured to communicate with a WD configured with at least a first and a second TCI state is provided. The first TCI state is the currently active TCI state. The network node is further configured to transmit an indication to the WD to switch from the first TCI state to the second TCI state, wherein the WD determines whether to switch from the first TCI state to the second TCI state depending on whether a condition is met. In embodiments, the network node may be further configured to receive an indication from the WD indicating whether the switch to the second TCI state is performed in response to the transmitted indication. The network node may be further configured to receive the indication by being configured to receive information indicating one of: that the switch to the second TCI state is performed; or that the switch to the second TCI state is not performed. The network node may in embodiments be further configured to schedule a downlink channel on the second TCI state when the switch to the second TCI state is performed, and schedule the downlink channel on the first TCI state when the switch is not performed. The network node may be further configured to transmit configuration information to the WD configuring at least

39 one of: a condition-based TCI state switch procedure; the condition; how to determine that the condition is met.

[00107] According to embodiments, a non-transitory, computer-readable medium is provided. The non-transitory computer-readable medium stores computer-executable instructions that, when executed by processing circuitry of a WD configured to communicate data with a network node, configure the WD to perform operations corresponding to any of the methods described with reference to FIG.13b. Further, a computer program product is provided. The computer program product comprises computer-executable instructions that, when executed by processing circuitry of a WD configured to communicate data with a network node, configure the WD to perform operations corresponding to methods described with reference to FIG.13b.

[00108] According to embodiments, a non-transitory, computer-readable medium is provided. The non-transitory computer-readable medium stores computer-executable instructions that, when executed by processing circuitry of a network node configured to communicate with a WD, configure the network node to perform operations corresponding to any of the methods described with reference to FIG.12b. Further, a computer program product is provided. The computer program product comprises computer-executable instructions that, when executed by processing circuitry of a a network node configured to communicate with a WD, configure the network node to perform operations corresponding to any of the methods described with reference to FIG.12b.

[00109] As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and/or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software

40 embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and/or functionality described herein may be performed by, and/or associated to, a corresponding module, which may be implemented in software and/or firmware and/or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD- ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

[00110] Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

[00111] These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

41 [00112] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

[00113] It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[00114] Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

42 [00115] Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and sub-combination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and sub-combinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or sub-combination.

[00116] As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. 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,” “includes” and/or “including” when used herein, 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.

[00117] In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple

43 components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

[00118] In some embodiments described herein, the term “node” is used which can be a network node or a user equipment (UE). In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

[00119] The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, centralized baseband, C-RAN, transmission reception point (TRP), nodes in distributed antenna system (DAS), Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a WD or a radio network node.

[00120] In some embodiments, the non-limiting terms WD or a user equipment (UE) are used interchangeably. The WD herein can be any type of WD capable of communicating with a network node or another WD over radio signals in a cellular or mobile communication system.

44 Examples of WD include at least one of a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), vehicular to vehicular (V2V), machine type WD, MTC WD, WD capable of machine to machine (M2M) communication, PDA, tablet, smart phone, low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device, etc.

[00121] Also, in some embodiments the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell/multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

[00122] The term radio access technology, or RAT, may refer to any RAT e.g. UTRA, E- UTRA, narrow band internet of things (NB-IoT), WiFi, Bluetooth, next generation RAT, New Radio (NR), 4G, 5G, etc. Any of the equipment denoted by the term node, network node or radio network node may be capable of supporting a single or multiple RATs.

[00123] The term signal or radio signal used herein can be any physical signal or physical channel. Examples of DL physical signals are reference signal (RS) such as PSS, SSS, CSI-RS, DMRS signals in SS/PBCH block (SSB), discovery reference signal (DRS), CRS, PRS etc. RS may be periodic e.g. RS occasion carrying one or more RSs may occur with certain periodicity e.g. 20 ms, 40 ms etc. The RS may also be aperiodic. Each SSB carries NR-PSS, NR-SSS and NR-PBCH in 4 successive symbols. One or multiple SSBs are transmit in one SSB burst which

45 is repeated with certain periodicity e.g., 5 ms, 10 ms, 20 ms, 40 ms, 80 ms and 160 ms. The WD is configured with information about SSB on cells of certain carrier frequency by one or more SS/PBCH block Measurement Timing Configurations (SMTC). The SMTC comprising parameters such as SMTC periodicity, SMTC occasion length in time or duration, SMTC time offset with respect to reference time (e.g., serving cell’s SFN) etc. Therefore, SMTC occasion may also occur with certain periodicity e.g., 5 ms, 10 ms, 20 ms, 40 ms, 80 ms and 160 ms. Examples of UL physical signals are reference signal such as SRS, DMRS etc. The term physical channel refers to any channel carrying higher layer information e.g., data, control etc. Examples of physical channels are PBCH, NPBCH, PDCCH, PDSCH, sPUCCH, sPDSCH, sPUCCH, sPUSCH, MPDCCH, NPDCCH, NPDSCH, E-PDCCH, PUSCH, PUCCH, NPUSCH etc.

[00124] Note that although terminology from one particular wireless system, such as, for example, 3 GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

[00125] Note further, that functions described herein as being performed by a WD or a network node may be distributed over a plurality of wireless devices and/or network nodes. In other words, it is contemplated that the functions of the network node and WD described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

46 [00126] In one or more embodiments, the definition of a kind of group of conditions for criteria or single condition for a criterion for performing a TCI state update is introduced where fulfilling condition(s) or not is the precondition of TCI state update, either update is decided by the WD or network node.

[00127] The term TCI state change, TCI state switch, active TCI state switch, TCI state update are interchangeably used but all have the same meaning referring to change or switching of the active TCI state of the wireless device. The active TCI state is used by the WD for determining a receiving beam for receiving channels, e.g., PDCCH, PDSCH, etc. The TCI state change may be triggered by a command or message (e.g., MAC, DCI, RRC etc.) received by the WD from a network node, e.g., from serving base station. The command may include at least information (e.g., identifier, related RS such as SSB index, etc.) about the target TCI state which the WD is requested to switch, e.g., from the current active TCI state.

[00128] For consistency, the terms TCI state switch and TCI state switching are used interchangeably.

[00129] Transmitting in DL may pertain to transmission from the network or network node to the wireless device. Transmitting in uplink (UL) may pertain to transmission from the WD to the network or network node. Transmitting in sidelink (SL) may pertain to (direct) transmission from one WD to another. UL, DL and SL (e.g., SL transmission and reception) may be considered communication directions. In some variants, UL and DL may also be used to described wireless communication between network nodes, e.g. for wireless backhaul and/or relay communication and/or (wireless) network communication for example between base stations or similar network nodes, in particular communication terminating at such. It may be

47 considered that backhaul and/or relay communication and/or network communication is implemented as a form of SL or UL communication or similar thereto.

[00130] 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 disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[00131] It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings.

List of example embodiments:

Embodiment A1. A network node configured to communicate with a WD (WD), the network node configured to, and/or comprising a radio interface and/or comprising processing circuitry configured to: cause transmission of a command associated with switching the WD from a first transmission configuration indication, TCI, state to a second TCI state, the switching being based at least on at least one signal measurement associated with the first TCI state meeting at least one predefined criterion; and cause transmission of signaling based at least on the second TCI state.

48 Embodiment A2. The network node of Embodiment Al, wherein the processing circuitry is further configured to: receive measurement information associated with the at least one signal measurement; determine whether the at least one signal measurement meets the at least one predefined criterion, the transmission of signaling based on at least the second TCI state being based on determining that the at least one signal measurement meets the at least one predefined criterion.

Embodiment A3. The network node of Embodiment Al, wherein the command is configured to cause the WD to determine whether at least one signal measurement performed by the WD meets the at least one predefined criterion; and the processing circuitry is further configured to receive an indication that the WD has switched to the second TCI state, the indication being based at least on the determination performed by the wireless device, the causing of transmission of signaling based at least on the second TCI state being based on the received indication.

Embodiment A4. The network node of any one of Embodiments A1-A3, wherein the at least one predefined criterion includes at least one of: comparing a signal level of a target beam to a first threshold; comparing a signal level of a source beam to a second threshold; comparing the signal level of the source beam to the signal level of the target beam; comparing a WD location to a predefined location threshold; and comparing a WD trajectory to the predefined location threshold.

Embodiment Bl. A method implemented in a network node that is configured to communicate with a wireless device, the method comprising:

49 causing transmission of a command associated with switching the WD from a first transmission configuration indication, TCI, state to a second TCI state, the switching being based at least on at least one signal measurement associated with the first TCI state meeting at least one predefined criterion; and causing transmission of signaling based at least on the second TCI state.

Embodiment B2. The method of Embodiment B 1 , further comprising: receiving measurement information associated with the at least one signal measurement; and determining whether the at least one signal measurement meets the at least one predefined criterion, the transmission of signaling based on at least the second TCI state being based on determining that the at least one signal measurement meets the at least one predefined criterion.

Embodiment B3. The method of Embodiment B 1 , wherein the command is configured to cause the WD to determine whether at least one signal measurement performed by the WD meets the at least one predefined criterion; and the method further comprising receiving an indication that the WD has switched to the second TCI state, the indication being based at least on the determination performed by the wireless device, the causing of transmission of signaling based at least on the second TCI state being based on the received indication.

Embodiment B4. The method of any one of Embodiments B1-B3, wherein the at least one predefined criterion includes at least one of: comparing a signal level of a target beam to a first threshold; comparing a signal level of a source beam to a second threshold;

50 comparing the signal level of the source beam to the signal level of the target beam; comparing a WD location to a predefined location threshold; and comparing a WD trajectory to the predefined location threshold.

Embodiment Cl. A WD (WD) configured to communicate with a network node, the WD configured to, and/or comprising a radio interface and/or processing circuitry configured to: receive a command associated with switching the WD from a first transmission configuration indication, TCI, state to a second TCI state; perform at least one signal measurement associated with a first TCI state; perform switching to the second TCI state, the switching being based at least on the at least one signal measurement of the WD meeting at least one predefined criterion; and receive signaling based at least on the switching to the second TCI state.

Embodiment C2. The WD of Embodiment Cl, wherein the processing circuitry is further configured to: determine whether the at least one signal measurement meets the at least one predefined criterion, the switching being based at least on the determination that the at least one signal measurement meets the at least one predefined criterion; and cause transmission of an indication that the WD has switched to the second TCI state. Embodiment C3. The WD of Embodiment Cl, wherein the processing circuitry is further configured to: transmit measurement information associated with the at least one signal measurement to allow the network node to determine whether the at least one signal measurement meets the at least one predefined criterion, the receiving of signaling based at least on the switching to the

51 second TCI state being based on that determination that the at least one signal measurement meets the at least one predefined criterion.

Embodiment D1. A method implemented in a WD (WD) that is configured to communicate with a network node, the method comprising: receiving a command associated with switching the WD from a first transmission configuration indication, TCI, state to a second TCI state; performing at least one signal measurement associated with a first TCI state; performing switching to the second TCI state, the switching being based at least on the at least one signal measurement of the WD meeting at least one predefined criterion; and receiving signaling based at least on the switching to the second TCI state.

Embodiment D2. The method of Embodiment D 1 , further comprising: determining whether the at least one signal measurement meets the at least one predefined criterion, the switching being based at least on the determination that the at least one signal measurement meets the at least one predefined criterion; and causing transmission of an indication that the WD has switched to the second TCI state. Embodiment D3. The method of Embodiment D 1 , further comprising transmitting measurement information associated with the at least one signal measurement to allow the network node to determine whether the at least one signal measurement meets the at least one predefined criterion, the receiving of signaling based at least on the switching to the second TCI state being based on that determination that the at least one signal measurement meets the at least one predefined criterion.

52

Claims

1. A method implemented in a wireless device, WD, configured to communicate with a network node, the WD being further configured with at least a first and a second transmission configuration indication, TCI, state, wherein the first TCI state is the currently active TCI state, the method comprising: receiving (S1310) an indication from the network node to switch from the first TCI state to the second TCI state; determining (SI 320) whether a condition for the switch from the first TCI state to the second TCI state is met; in response to the received indication to switch, performing (SI 330) the switch to the second TCI state when determining that the condition for the switch is met, and refraining from performing (SI 340) the switch to the second TCI state otherwise.

2. The method of claim 1, further comprising: indicating (SI 350) to the network node whether the switch to the second TCI state is performed.

3. The method of claim 2, wherein indicating comprises transmitting information indicating: that the switch to the second TCI state is performed; or that the switch to the second TCI state is not performed.

4. The method of any of the preceding claims, further comprising:

53 receiving configuration information from the network node configuring at least one of: a condition-based TCI state switch procedure; the condition; how to determine that the condition is met.

5. The method of any of the preceding claims, wherein the currently active TCI state is associated with a downlink reference signal and is used to determine a receiving beam for receiving a downlink channel.

6. The method of any of the preceding claims, wherein the indication to switch is a command received in one of: a Medium Access Control message, a Radio Resource Control message, and a Downlink Control Information message.

7. The method of any of the preceding claims, wherein determining whether the condition is met comprises at least one of: determining whether a signal level of a target beam meets a first threshold (HI); determining whether a signal level of a serving beam meets a second threshold (H2); determining whether a comparison of the signal level of the serving beam (Ss) to the signal level of the target beam (St) meets the condition.

8. The method of any of the preceding claims, wherein determining whether the condition is met is based on a position of the WD (PI).

54

9. A method implemented in a network node that is configured to communicate with a wireless device, WD, configured with at least a first and a second transmission configuration indication, TCI, state, wherein the first TCI state is the currently active TCI state, the method comprising: transmitting (SI 410) an indication to the WD to switch from the first TCI state to the second TCI state, wherein the WD determines whether to switch from the first TCI state to the second TCI state depending on whether a condition is met.

10. The method of claim 9, further comprising: receiving (SI 420) an indication from the WD indicating whether the switch to the second TCI state is performed in response to the transmitted indication.

11. The method of claim 10, wherein receiving (SI 420) the indication comprises one of: receiving information indicating that the switch to the second TCI state is performed; or receiving information indicating that the switch to the second TCI state is not performed.

12. The method of any of claims 9-11, further comprising: scheduling (SI 430) a downlink channel on the second TCI state when the switch to the second TCI state is performed, and scheduling the downlink channel on the first TCI state when the switch is not performed.

13. The method of any of the claims 9-12, further comprising:

55 transmitting configuration information to the WD configuring at least one of: a condition- based TCI state switch procedure; the condition; how to determine that the condition is met.

14. A wireless device, WD, (22) configured to communicate with a network node (16), and further configured with at least a first and a second transmission configuration indication, TCI, state, wherein the first TCI state is the currently active TCI state, the WD being configured to: receive an indication from the network node to switch from the first TCI state to the second TCI state; determine whether a condition for the switch from the first TCI state to the second TCI state is met; in response to the received indication to switch, perform the switch to the second TCI state when determining that the condition for the switch is met, and refrain from performing the switch to the second TCI state otherwise.

15. The WD of claim 14, further configured to: indicate to the network node whether the switch to the second TCI state is performed.

16. The WD of claim 15, further configured to indicate by being configured to transmit information indicating one of: that the switch to the second TCI state is performed; or that the switch to the second TCI state is not performed.

17. The WD of any of claims 14-16, further configured to:

56 receive configuration information from the network node configuring at least one of: a condition-based TCI state switch procedure; the condition; how to determine that the condition is met.

18. The WD of any of claims 14-17, wherein the currently active TCI state is associated with a downlink reference signal and is used to determine a receiving beam for receiving a downlink channel.

19. The WD of any of claims 14-18, further configured to receive the indication to switch in a command in one of: a Medium Access Control message, a Radio Resource Control message, and a Downlink Control Information message.

20. The WD of any of claims 14-19, further configured to determine whether the condition is met by being configured to determine at least one of: whether a signal level of a target beam meets a first threshold (HI); whether a signal level of a serving beam meets a second threshold (H2); whether a comparison of the signal level of the serving beam (Ss) to the signal level of the target beam (St) meets the condition.

21. The WD of any of claims 14-20, further configured to determine whether the condition is met based on a position of the WD (PI).

57

22. A network node (16) configured to communicate with a wireless device, WD, (22) configured with at least a first and a second transmission configuration indication, TCI, state, wherein the first TCI state is the currently active TCI state, the network node being further configured to: transmit an indication to the WD to switch from the first TCI state to the second TCI state, wherein the WD determines whether to switch from the first TCI state to the second TCI state depending on whether a condition is met.

23. The network node of claim 22, further configured to: receive an indication from the WD indicating whether the switch to the second TCI state is performed in response to the transmitted indication.

24. The network node of claim 23, further configured to receive the indication by being configured to receive information indicating one of: that the switch to the second TCI state is performed; or that the switch to the second TCI state is not performed.

25. The network node of any of claims 22-24, further configured to: schedule a downlink channel on the second TCI state when the switch to the second TCI state is performed, and schedule the downlink channel on the first TCI state when the switch is not performed.

26. The network node of any of claims 22-25, further configured to:

58 transmit configuration information to the WD configuring at least one of: a condition- based TCI state switch procedure; the condition; how to determine that the condition is met.

27. A wireless device, WD, configured to communicate with a network node, and further configured with at least a first and a second transmission configuration indication, TCI, state, wherein the first TCI state is the currently active TCI state, the WD comprising a processing circuitry configured to perform operations corresponding to any of the methods of claims 1-8.

28. A network node configured to communicate with a wireless device, WD, configured with at least a first and a second transmission configuration indication, TCI, state, wherein the first TCI state is the currently active TCI state, the network node comprising a processing circuitry configured to perform operations corresponding to any of the methods of claims 9-13.

29. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a wireless device, WD, configured to communicate data with a network node, configure the WD to perform operations corresponding to any of the methods of claims 1-8.

30. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a wireless device, WD, configured to communicate data with a network node, configure the WD to perform operations corresponding to any of the methods of claims 1-8.

59

31. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a network node configured to communicate with a wireless device, WD, configure the network node to perform operations corresponding to any of the methods of claims 9-13.

32. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a a network node configured to communicate with a wireless device, WD, configure the network node to perform operations corresponding to any of the methods of claims 9-13.

60