WO2025189794A1

WO2025189794A1 - Methods and apparatuses for a layer-1 (l1) event measurement report and conditional l1/l2-triggered mobility (ltm)

Info

Publication number: WO2025189794A1
Application number: PCT/CN2024/130583
Authority: WO
Inventors: Lianhai WU; Le Yan; Bingchao LIU; Ran YUE
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2024-11-07
Filing date: 2024-11-07
Publication date: 2025-09-18
Anticipated expiration: 2027-05-07

Abstract

Various aspects of the present application relate to methods and apparatuses for a layer-1 (L1) event measurement report and conditional L1/L2-Triggered Mobility (LTM). According to an embodiment of the present application, a user equipment (UE) includes at least one memory and at least one processor coupled to the at least one memory and configured to cause the UE to: receive a configuration including information of at least one event for a layer-1 (L1) measurement report; evaluate whether the at least one event is fulfilled during a time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the time window; and receive another configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE. After receiving the updated configuration, the UE may reset the time window or continue maintaining the time window. Furthermore, the UE may receive an LTM candidate configuration and the corresponding execution condition related to a candidate cell. Once the execution condition is met or the UE receives an LTM command for this candidate cell, the UE performs cell switch towards the candidate cell.

Description

METHODS AND APPARATUSES FOR A LAYER-1 (L1) EVENT MEASUREMENT REPORT AND CONDITIONAL L1/L2-TRIGGERED MOBILITY (LTM)

TECHNICAL FIELD

The present application relates to wireless communications, and more specifically to methods and apparatuses for a layer-1 (L1) event measurement report and conditional L1/L2-Triggered Mobility (LTM) .

BACKGROUND

A wireless communications system may include one or multiple network communication devices, such as base stations (BSs) , which may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE) , or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g. time-domain resources (e.g. symbols, slots, subframes, frames, or the like) or frequency-domain resources (e.g. subcarriers, carriers, or the like) . Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g. sixth generation (6G) ) .

SUMMARY

An article "a" before an element is unrestricted and understood to refer to "at least one" of those elements or "one or more" of those elements. The terms "a, " "at least one, " "one or more, " and "at least one of one or more" may be interchangeable. As used herein, including in the claims, "or" as used in a list of items (e.g. a list of items prefaced by a phrase such as "at least one of" or "one or more of" or "one or both of" ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase "based on" shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as "based on condition A" may be based on both a condition A and a condition B without departing from the scope of the present application. In other words, as used herein, the phrase "based on" shall be construed in the same manner as the phrase "based at least in part on. Further, as used herein, including in the claims, a "set" may include one or more elements.

Some implementations of the present application provide a user equipment (UE) . The UE includes at least one memory; and at least one processor coupled to the at least one memory and configured to cause the UE to: receive a first configuration including information of at least one event for a layer-1 (L1) measurement report; evaluate whether the at least one event is fulfilled during a first time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the first time window; and receive a second configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

In some implementations of the UE described herein, the at least one event includes at least one of the following: a current beam of a serving cell of the UE becomes worse than a first threshold; any beam of at least one candidate cell becomes an amount of offset better than the current beam of the serving cell; any beam of the at least one candidate cell becomes better than a second threshold; or the current beam of the serving cell becomes worse than a third threshold and any beam of the at least one candidate cell becomes better than a fourth threshold, and wherein the information of the at least one event includes at least one of the following: identifier (ID) information of the at least one event; one or more offsets for the at least one event; one or more hysteresis parameters for the at least one event; one or more thresholds for the at least one event; one or more filter parameters for the at least one event; or a length of a time window associated with the at least one event.

In some implementations of the UE described herein, the second configuration is carried in at least one of the following: downlink control information (DCI) ; a medium access control (MAC) control element (CE) ; or a radio resource control (RRC) reconfiguration message.

In some implementations of the UE described herein, at least one of the current beam of the serving cell or the set of beams of the at least one candidate cell is: a synchronization signal block (SSB) index; or a channel state information reference signal (CSI-RS) .

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to reset the first time window, if at least one of following conditions occurs according to the second configuration during the first time window: the current beam of the serving cell is changed; a measurement reference signal (RS) corresponding to the current beam of the serving cell is changed; a transmission configuration indicator (TCI) state corresponding to the current beam of the serving cell is changed; the set of beams of the at least one candidate cell is updated; one or more beams within the set of beams of the at least one candidate cell are removed, if the one or more beams can meet at least one entering condition; a reception of a candidate cell TCI states activation MAC CE on the serving cell; or a reception of a candidate cell TCI states deactivation MAC CE on the serving cell.

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to maintain the first time window, if at least one of following conditions occurs according to the second configuration during the first time window: the current beam of the serving cell is changed; a measurement reference signal (RS) corresponding to the current beam of the serving cell is changed; a transmission configuration indicator (TCI) state corresponding to the current beam of the serving cell is changed; or the set of beams of the at least one candidate cell is updated.

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to: receive a reconfiguration message including an L1/L2-Triggered Mobility (LTM) candidate configuration associated with one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells; evaluate whether an execution condition within the set of execution conditions is fulfilled during a second time window; and receive an LTM cell switch command associated with a first LTM candidate cell within the one or more LTM candidate cells, wherein the LTM cell switch command includes a first early timing advance (TA) value and identifier (ID) information of the first LTM candidate cell.

In some implementations of the UE described herein, after reception of the LTM cell switch command, the at least one processor is further configured to cause the UE to prohibit to perform an LTM cell switch towards the first LTM candidate cell.

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to start a time alignment timer (TAT) for the first early TA value included in the LTM cell switch command.

In some implementations of the UE described herein, the LTM cell switch command includes an activated TCI state associated with the first LTM candidate cell, and the at least one processor is further configured to cause the UE to: ignore the activated TCI state; or store the activated TCI state and apply the activated TCI state when performing an LTM cell switch towards the first LTM candidate cell.

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to: once an execution condition corresponding to a second LTM candidate cell within the one or more LTM candidate cells is fulfilled during the second time window, trigger to perform an LTM cell switch towards the second LTM candidate cell and start an LTM timer for the LTM cell switch; and if the first early TA value associated with the first LTM candidate cell is still valid when the execution condition corresponding to the first LTM candidate cell is fulfilled, perform a random access channel (RACH) -less LTM cell switch towards the first LTM candidate cell by using the first early TA value.

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to: receive a reconfiguration message including an L1/L2-Triggered Mobility (LTM) candidate configuration associated with one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells; evaluate whether an execution condition within the set of execution conditions is fulfilled during a third time window; receive a first set of early timing advance (TA) values associated with the one or more LTM candidate cells and identifier (ID) information of the one or more LTM candidate cells; and receive an LTM cell switch command associated with a third LTM candidate cell within the one or more LTM candidate cells.

In some implementations of the UE described herein, the first set of early TA values and the ID information are carried in at least one of the following: downlink control information (DCI) ; a medium access control (MAC) control element (CE) ; or a radio resource control (RRC) configuration.

In some implementations of the UE described herein, the first set of early TA values and the ID information are received from a source distributed units (DU) of a base station (BS) associated with the serving cell before the execution condition within the set of execution conditions is fulfilled during the third time window.

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to: if the LTM cell switch command includes a third early TA value associated with the third LTM candidate cell, and if a second early TA value associated with the third LTM candidate cell is provided in the first set of early TA values before the third early TA value is provided, perform a random access channel (RACH) -less LTM cell switch towards the third LTM candidate cell by using the third early TA value; or if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is still valid, perform a RACH-less LTM cell switch towards the third LTM candidate cell by using the second early TA value; or if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is invalid, perform a RACH based LTM cell switch towards the third LTM candidate cell without using the second early TA value.

In some implementations of the UE described herein, the at least one processor is further configured to cause the UE to stop evaluating the execution condition corresponding to the third LTM candidate cell, once the RACH-less LTM cell switch or the RACH based LTM cell switch towards the third LTM candidate cell is triggered.

Some implementations of the present application provide a processor of a user equipment (UE) for wireless communication, comprising at least one controller coupled with at least one memory and configured to cause the processor to: receive a first configuration including information of at least one event for a layer-1 (L1) measurement report; evaluate whether the at least one event is fulfilled during a first time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the first time window; and receive a second configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

Some implementations of the present application provide a method performed by a user equipment (UE) . The method includes: receiving a first configuration including information of at least one event for a layer-1 (L1) measurement report; evaluating whether the at least one event is fulfilled during a first time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the first time window; and receiving a second configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

Some implementations of the present application provide a base station (BS) . The BS includes at least one memory; and at least one processor coupled to the at least one memory and configured to cause the BS to: receive, from a user equipment (UE) , capability information indicating that the UE supports an event based layer-1 (L1) measurement report; transmit, to the UE, a first configuration including information of at least one event for an L1 measurement report; and transmit, to the UE, a second configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

In some implementations of the BS described herein, the at least one event includes at least one of the following: a current beam of a serving cell of the UE becomes worse than a first threshold; any beam of at least one candidate cell becomes an amount of offset better than the current beam of the serving cell; any beam of the at least one candidate cell becomes better than a second threshold; or the current beam of the serving cell becomes worse than a third threshold and any beam of the at least one candidate cell becomes better than a fourth threshold, and wherein the information of the at least one event includes at least one of the following: identifier (ID) information of the at least one event; one or more offsets for the at least one event; one or more hysteresis parameters for the at least one event; one or more thresholds for the at least one event; one or more filter parameters for the at least one event; or a length of a time window associated with the at least one event.

In some implementations of the BS described herein, the second configuration is carried in at least one of the following: downlink control information (DCI) ; a medium access control (MAC) control element (CE) ; or a radio resource control (RRC) reconfiguration message.

In some implementations of the BS described herein, at least one of the current beam of the serving cell or the set of beams of the at least one candidate cell is: a synchronization signal block (SSB) index; or a channel state information reference signal (CSI-RS) .

In some implementations of the BS described herein, the at least one processor is further configured to cause the BS to: transmit, to the UE, a reconfiguration message including an L1/L2-Triggered Mobility (LTM) candidate configuration associated with one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells; and transmit, to the UE, an LTM cell switch command associated with a first LTM candidate cell within the one or more LTM candidate cells, wherein the LTM cell switch command includes a first early timing advance (TA) value and identifier (ID) information of the first LTM candidate cell.

In some implementations of the BS described herein, after reception of the LTM cell switch command, an LTM cell switch towards the first LTM candidate cell is prohibited to be performed at the UE.

In some implementations of the BS described herein, the LTM cell switch command includes an activated TCI state associated with the first LTM candidate cell, and the activated TCI state can be ignored by the UE or can be applied by the UE when performing an LTM cell switch towards the first LTM candidate cell.

In some implementations of the BS described herein, the at least one processor is further configured to cause the BS to: transmit, to the UE, a reconfiguration message including an L1/L2-Triggered Mobility (LTM) candidate configuration associated with one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells; transmit, to the UE, a first set of early timing advance (TA) values associated with the one or more LTM candidate cells and identifier (ID) information of the one or more LTM candidate cells; and transmit, to the UE, an LTM cell switch command associated with a third LTM candidate cell within the one or more LTM candidate cells.

In some implementations of the BS described herein, the first set of early TA values and the ID information are carried in at least one of the following: downlink control information (DCI) ; a medium access control (MAC) control element (CE) ; or a radio resource control (RRC) configuration.

In some implementations of the BS described herein, the first set of early TA values and the ID information are transmitted by a source distributed units (DU) of the BS associated with the serving cell before the execution condition within the set of execution conditions is fulfilled during a corresponding time window.

In some implementations of the BS described herein, if the LTM cell switch command includes a third early TA value associated with the third LTM candidate cell, and if a second early TA value associated with the third LTM candidate cell is provided in the first set of early TA values before the third early TA value is provided, a random access channel (RACH) -less LTM cell switch towards the third LTM candidate cell can be performed by the UE using the third early TA value; or if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is still valid, a RACH-less LTM cell switch towards the third LTM candidate cell can be performed by the UE using the second early TA value; or if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is invalid, a RACH based LTM cell switch towards the third LTM candidate cell can be performed by the UE without using the second early TA value.

In some implementations of the BS described herein, the BS includes a centralized unit (CU) , a source distributed units (DU) managing the serving cell, and at least one candidate DU managing one or more LTM candidate cells, and wherein the at least one processor is further configured to cause the CU to: determine to initiate condition based LTM mobility; and transmit a request to the at least one candidate DU, wherein the request includes: identifier (ID) information of a target candidate cell within the one or more LTM candidate cells; and information indicating that the request is associated with the condition based LTM mobility.

In some implementations of the BS described herein, the at least one processor is further configured to cause the CU to: transmit, to the source DU and the UE, an LTM candidate configuration associated with the one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells; and transmit, to the source DU and the UE, information indicating that an LTM cell switch command associated with an LTM candidate cell within the one or more LTM candidate cells is allowed to be transmitted.

In some implementations of the BS described herein, the at least one processor is further configured to cause the CU to decide whether the LTM cell switch command can be used to trigger an LTM cell switch towards the LTM candidate cell.

Some implementations of the present application provide a processor of a base station (BS) for wireless communication, comprising at least one controller coupled with at least one memory and configured to cause the processor to: receive, from a user equipment (UE) , capability information indicating that the UE supports an event based layer-1 (L1) measurement report; transmit, to the UE, a first configuration including information of at least one event for an L1 measurement report; and transmit, to the UE, a second configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

Some implementations of the present application provide a method performed by a base station (BS) . The method includes: receiving, from a user equipment (UE) , capability information indicating that the UE supports an event based layer-1 (L1) measurement report; transmitting, to the UE, a first configuration including information of at least one event for an L1 measurement report; and transmitting, to the UE, a second configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates an example of a wireless communications system in accordance with aspects of the present application.

Figure 2 illustrates an example of a user equipment (UE) 200 in accordance with aspects of the present application.

Figure 3 illustrates an example of a processor 300 in accordance with aspects of the present application.

Figure 4 illustrates an example of a network equipment (NE) 400 in accordance with aspects of the present application.

Figures 5 and 6 illustrate flowcharts related to an L1 event measurement report and conditional LTM in accordance with aspects of the present application.

Figures 7 and 8 illustrate schematic diagrams of an L1 event measurement report and conditional LTM in accordance with aspects of the present application.

DETAILED DESCRIPTION

In general, when a UE moves from one cell to another cell, at some point a serving cell change needs to be performed. In the legacy, the serving cell change is done by explicit radio resource control (RRC) reconfiguration signalling (e.g. a handover (HO) command) to trigger the synchronization of a target cell based on Layer-3 (L3) measurements report. It leads to longer latency, larger overhead, and longer interruption time than beam level mobility. Therefore, in 3GPP, LTM was approved to change a serving cell via L1/L2 signalling, in order to reduce the latency, overhead and interruption time.

Layer 1/layer 2 (L1/L2) triggered mobility (LTM) is a procedure in which a network equipment (e.g. a BS) receives L1 measurement report (s) from a UE, and on their basis the BS changes UE’s serving cell by a cell switch command signaled via a medium access control (MAC) control element (CE) . The cell switch command indicates an LTM candidate cell configuration that the BS previously prepared and provided to the UE through RRC signalling. Then the UE switches to the target cell according to the cell switch command. The LTM can be used to reduce the mobility latency. LTM may also be named as L1/L2 lower layer-Triggered Mobility or the like.

Master cell group (MCG) LTM is a PCell switch procedure that the network triggers via a MAC CE based on L1 measurements. Secondary cell group (SCG) LTM is a PSCell switch procedure that the network triggers via a MAC CE based on L1 measurements.

In an MCG LTM procedure or an LTM PCell switch procedure from a source cell (or source PCell) to a target cell (or target PCell) in a dual connectivity scenario, a node which generates an RRC Reconfiguration message for the MCG LTM switch procedure or the LTM PCell switch procedure, or which determines to initiate MCG LTM may be a MN or a CU of the MN.

In an SCG LTM procedure or an LTM PSCell switch procedure from a source PSCell to a target PSCell in a dual connectivity scenario, a node which generates an RRC Reconfiguration message for the SCG LTM switch procedure or the LTM PSCell switch procedure, or which determines to initiate SCG LTM may be a MN or an SN or a CU of the MN or a CU of the SN, furthermore, the SN may be a node to which the serving PSCell or source PSCell belongs (e.g. a source SN) , or the SN may be a node to which the target PSCell for LTM belongs (e.g. a target SN) .

Currently, the following LTM events based on beam specific quality of a serving cell and candidate cells may be supported as L1 LTM measurement events.

- Event #1: Beam (s) of a serving cell becomes worse than an absolute threshold;

- Event #2: Beam (s) of a candidate cell becomes offset better than beam (s) of a serving cell;

- Event #3: Beam (s) of a candidate cell becomes better than an absolute threshold;

- Event #4: Beam (s) of a serving cell becomes worse than an absolute threshold AND Beam (s) of a candidate cell becomes better than another absolute threshold.

For example, solution for E1 (Event #1: Beam (s) of a serving cell becomes worse than an absolute threshold) is as follows:

(1) Entering condition:

- Option E1-1a: A number m is configured by network. If m =1, it is fixed in the specification. Namely, the configuration from network is not needed.

- Alternative#1: UE considers the entering condition for this event to be fulfilled when condition E1-1 is fulfilled for the best beam.

- Alternative#2: UE considers the entering condition for this event to be fulfilled when condition E1-1 is fulfilled for the mth beam.

- Alternative#3: UE considers the entering condition for this event to be fulfilled when condition E1-1 is fulfilled based on the average of the m beams.

The m beams could be the best m beams from the serving cell in this option.

- Option E1-1b: A number m and threshold for beam filtering are configured by network.

- UE considers the entering condition for this event to be fulfilled when condition E1-1 is fulfilled based on the average of the best minimum (m1, m) beams. There are m1 beams of the serving cell meeting the threshold. Ms is the average of minimum (m1, m) beams of the serving cell.

(2) Leaving condition:

- Option E1-2a: A number m is configured by network. If m =1, it is fixed in the specification. Namely, the configuration from network is not needed.

- Alternative#1: UE considers the leaving condition for this event to be fulfilled when condition E1-2 is fulfilled for the best m beams.

- Alternative#2: UE considers the leaving condition for this event to be fulfilled when condition E1-2 is fulfilled based on the average of the m beams.

The m beams could be the best m beams from the serving cell in this option.

- Option E1-2b: A number m and threshold for beam filtering are configured by network.

- UE considers the entering condition for this event to be fulfilled when condition E1-2 is fulfilled based on the average of the best minimum (m1, m) beams. There are m1 beams of the serving cell meeting the threshold. Ms is the average of minimum (m1, m) beams of the serving cell.

Inequality E1-1 (Entering condition)

Mbs + Hys < Thresh

Inequality E1-2 (Leaving condition)

Mbs - Hys > Thresh

The variables in the formula are defined as follows:

Mbs is the measurement result of the beam of the serving cell.

Hys is the hysteresis parameter for this event.

Thresh is the threshold parameter for this event.

Solution for E2 (Event #2: Beam (s) of a candidate cell becomes offset better than beam (s) of a serving cell) is as follows:

(1) Entry condition:

- Option E2-1a: A number m is configured by network.

- Alternative#1: UE considers the entering condition for this event to be fulfilled when condition E2-1 is fulfilled for each beam from the best m beams.

- Alternative#2: UE considers the entering condition for this event to be fulfilled when condition E2-1 is fulfilled based on the average of the best m beams.

- Option E2-1b: A number m and a threshold for beam filtering is configured by network.

- Alternative#1: UE considers the entering condition for this event to be fulfilled when condition E2-1 is fulfilled for each beam from the best minimum (m1, m2 and m) beams. The number m is configured by network. One threshold is configured by the network to UE. Only the beam which is greater than the threshold can be selected for checking entering or leaving condition. There are m1 beams of the serving cell meeting the threshold. There are m2 beams of the serving cell meeting the threshold.

√ For example, if Mn used in E2-1 is the best beam from the neighbour cell, Mp used in E2-2 is also the best beam from the serving cell. If Mn used in E2-1 is the second-best beam from the neighbour cell, Mp used in E2-2 is also the second-best beam from the serving cell. And so on.

- Alternative#2: UE considers the entering condition for this event to be fulfilled when condition E2-2 is fulfilled based on the average of beams of serving cell and neighbour cell. There are m1 beams of the serving cell meeting the threshold. There are m2 beams of the neighbour cell meeting the threshold. Mn is the average of minimum (m2, m) beams of neighbour cell. Mp is the average of minimum (m1, m) beams of serving cell.

(2) Leaving condition:

- Option E2-2a: A number m is configured by network.

- Alternative#1: UE considers the leaving condition for this event to be fulfilled when condition E2-2 is fulfilled for one of the best m beams.

- Alternative#2: UE considers the leaving condition for this event to be fulfilled when condition E2-2 is fulfilled based on the average of the best m beams.

- Option E2-2b: A number m and a threshold for beam filtering is configured by network.

- Alternative#1: UE considers the leaving condition for this event to be fulfilled when condition E2-2 is fulfilled for one beam from serving cell and neighbour cell, which is one of the best minimum (m1, m2 and m) beams. The number m is configured by network. One threshold may be configured for UE. Only the beam which is greater than the threshold can be selected for checking leaving condition. There are m1 beams of the serving cell meeting the threshold. There are m2 beams of the neighbour cell meeting the threshold.

√ For example, if Mbn used in E2-2 is the best beam of the best f minimum (m1, m2 and m) beams from the neighbour cell, Mbp used in E2-2 is also the best beam of the best f minimum (m1, m2 and m) beams from the serving cell. If Mn used in E2-2 is the second-best beam from the neighbour cell, Mbp used in E2-2 is also the second-best beam from the serving cell. And so on.

- Alternative#2: UE considers the leaving condition for this event to be fulfilled when condition E2-2 is fulfilled based on the average of beams of serving cell and neighbour cell. There are m1 beams of the serving cell meeting the threshold. There are m2 beams of the neighbour cell meeting the threshold. Mn is the average of best minimum (m2, m) beams of neighbour cell. Mp is the average of the best minimum (m2, m) beams of serving cell. Or the average for the serving cell can be calculated based on the minimum (m1, m2, m) beams of serving cell. The average for the neighbour cell can be calculated based on the minimum (m1, m2, m) beams of neighbour cell.

- use the SpCell for Mbp, Ofp and Ocp.

Inequality E2-1 (Entering condition)

Mbn + Ofn + Ocn - Hys > Mbp + Ofp + Ocp + Off

Inequality E2-2 (Leaving condition)

Mbn + Ofn + Ocn + Hys < Mbp + Ofp + Ocp + Off

The variables in the formula are defined as follows:

Mbn is the measurement result of the beam of the neighbouring cell.

Ofn is the measurement object specific offset of the reference signal of the neighbour cell.

Ocn is the cell specific offset of the neighbour cell.

Mbp is the measurement result of the SpCell.

Ofp is the measurement object specific offset of the SpCell (i.e. offsetMO as defined within measObjectNR corresponding to the SpCell) .

Ocp is the cell specific offset of the SpCell (i.e. cellIndividualOffset as defined within measObjectNR corresponding to the SpCell) , and is set to zero if not configured for the SpCell.

Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigNR for this event) .

Solution for E3 (Event #3: Beam (s) of a candidate cell becomes better than an absolute threshold) is as follows:

(1) Entering condition:

- Option E3-1a: A number m is configured by network. If m =1, it is fixed in the specification. Namely, the configuration from network is not needed.

- Alternative#1: UE considers the entering condition for this event to be fulfilled when condition E3-1 is fulfilled for the m beams.

- Alternative#2: UE considers the entering condition for this event to be fulfilled when condition E3-1 is fulfilled based on the average of the m beams.

The m beams could be the best m beams from the serving cell in this option.

(2) Leaving condition:

- Option E3-2a: A number m is configured by network. If m =1, it is fixed in the specification. Namely, the configuration from network is not needed.

- Alternative#1: UE considers the leaving condition for this event to be fulfilled when condition E3-2 is fulfilled for the best beam.

- Alternative#2: UE considers the leaving condition for this event to be fulfilled when condition E3-2 is fulfilled for the mth beam (based on the beam quality) .

- Alternative#3: UE considers the leaving condition for this event to be fulfilled when condition E3-2 is fulfilled for any one beam from the best m beams.

- Alternative#4: UE considers the leaving condition for this event to be fulfilled when condition E3-2 is fulfilled based on the average of the m beams.

The m beams could be the best m beams from the serving cell in this option.

- Option E3-2b: A number m and threshold for beam filtering are configured by network.

- UE considers the entering condition for this event to be fulfilled when condition E1-1 is fulfilled based on the average of the best minimum (m1, m) beams. There are m1 beams of the neighbour cell meeting the threshold. Mbs is the average of minimum (m1, m) beams of the neighbour cell.

Inequality E3-1 (Entering condition)

Mbn + Ofn + Ocn - Hys > Thresh

Inequality E3-2 (Leaving condition)

Mbn + Ofn + Ocn + Hys < Thresh

The variables in the formula are defined as follows:

Mbn is the measurement result of the neighbouring cell or the measurement result of serving PSCell (i.e., in case it is configured as candidate PSCell for CondEvent E3 evaluation) for CHO with candidate SCG (s) case.

Ofn is the measurement object specific offset of the neighbour cell (i.e. offsetMO as defined within measObjectNR corresponding to the neighbour cell) .

Ocn is the measurement object specific offset of the neighbour cell (i.e. cellIndividualOffset as defined within measObjectNR corresponding to the neighbour cell, or cellIndividualOffset as defined within reportConfigNR) , and set to zero if not configured for the neighbour cell.

Hys is the hysteresis parameter for this event.

Thresh is the threshold parameter for this event.

Solution for E4 (Event #4: Beam (s) of a serving cell becomes worse than an absolute threshold AND Beam (s) of a candidate cell becomes better than another absolute threshold) is as follows:

(1) Entering condition:

- Option E4-1a: A number m is configured by network. If m =1, it is fixed in the specification. Namely, the configuration from network is not needed.

- Alternative#1: UE considers the entering condition for this event to be fulfilled when condition E4-1 is fulfilled for the m beams from the serving cell and E4-2 is fulfilled for the m beams from the neighbour cell.

- Alternative#2: UE considers the entering condition for this event to be fulfilled when condition E4-1 is fulfilled based on the average of the m beams from the serving cell and condition E4-1 is fulfilled based on the average of the m beams from the neighbour cell.

The m beams could be the best m beams from the serving cell in this option.

(2) Leaving condition:

- Option E4-2a: A number m is configured by network. If m =1, it is fixed in the specification. Namely, the configuration from network is not needed.

- Alternative#1: UE considers the leaving condition for this event to be fulfilled when condition E4-3 is fulfilled for the best beam from the serving cell or condition E4-4 is fulfilled for the best beam from the neighbour cell.

- Alternative#2: UE considers the leaving condition for this event to be fulfilled when condition E4-3 is fulfilled for the mth beam from the serving cell or condition E4-4 is fulfilled for the mth beam from the neighbour cell.

- Alternative#3: UE considers the leaving condition for this event to be fulfilled when condition E4-3 is fulfilled for any one beam from the best m beams of the serving cell or condition E4-4 is fulfilled for any one beam from the best m beams of the neighbour cell.

- Alternative#4: UE considers the leaving condition for this event to be fulfilled when condition E4-3 is fulfilled based on the average of the m beams from the serving cell or condition E4-4 is fulfilled based on the average of the m beams from the neighbour cell.

The m beams could be the best m beams from the serving cell in this option.

- Option E4-2b: A number m and threshold for beam filtering are configured by network.

- UE considers the entering condition for this event to be fulfilled when condition E4-3 is fulfilled based on the average of the best minimum (m2, m) beams from serving cell or condition E4-4 is fulfilled based on the average of the best minimum (m1, m) beams from neighbour cell. There are m2 beams of the serving cell meeting the threshold. There are m1 beams of the neighbour cell meeting the threshold. Mbn is the average of minimum (m1, m) beams of the neighbour cell. Mbp is the average of minimum (m2, m) beams of the serving cell.

Inequality E4-1 (Entering condition 1)

Mbp + Hys < Thresh1

Inequality E4-2 (Entering condition 2)

Mbn + Ofn + Ocn - Hys > Thresh2

Inequality E4-3 (Leaving condition 1)

Mbp - Hys > Thresh1

Inequality E4-4 (Leaving condition 2)

Mbn + Ofn + Ocn + Hys < Thresh2

The variables in the formula are defined as follows:

Mbp is the measurement result of the beam from NR SpCell.

Mbn is the measurement result of the beam of the neighbouring cell.

Ocn is the cell specific offset of the neighbour cell, and set to zero if not configured for the neighbour cell.

Hys is the hysteresis parameter for this event.

Thresh1 is the threshold parameter for this event.

Thresh2 is the threshold parameter for this event.

In some cases, an LTM configuration includes the beam configuration of both synchronization signal block (SSB) and channel state information reference signal (CSI-RS) in L1 measurement resource configuration. However, the following details have not been discussed yet, including, e.g. : if the current beam of serving cell of a UE is changed, or if a beam configuration of one or more candidate cells is changed, what is a UE's behavior regarding a time window (e.g. time to trigger (TTT) ) for an event in which a serving cell of a UE is involved; or whether an LTM cell switch command can be used to trigger condition based LTM cell switch. This patent application aims to address such issues.

In the embodiments of the present disclosure, condition based LTM cell switch may also be named as "conditional LTM" or "condition based LTM mobility" or the like. An LTM candidate cells in condition based LTM cell switch may also be named as "a condition based LTM candidate cell" or the like. More details of the embodiments of the present application will be illustrated in the following text in combination with the appended drawings.

Figure 1 illustrates an example of a wireless communications system 100 in accordance with aspects of the present application. The wireless communications system 100 may include one or more NE 102, one or more UE 104, and a core network (CN) 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA) , frequency division multiple access (FDMA) , or code division multiple access (CDMA) , etc.

The one or more NE 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the NE 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN) , a NodeB, an eNodeB (eNB) , a next-generation NodeB (gNB) , or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g. receive signaling, transmit signaling) over a Uu interface.

An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g. voice, video, packet data, messaging, broadcast, etc. ) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN) . In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NE 102.

The one or more UE 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (IoT) device, an Internet-of-Everything (IoE) device, or machine-type communication (MTC) device, among other examples.

A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g. S1, N2, or network interface) . In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other or indirectly (e.g. via the CN 106. In some implementations, one or more NE 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC) . An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs) .

The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC) , or a 5G core (5GC) , which may include a control plane entity that manages access and mobility (e.g. a mobility management entity (MME) , an access and mobility management functions (AMF) ) and a user plane entity that routes packets or interconnects to external networks (e.g. a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g. data bearers, signal bearers, etc. ) for the one or more UEs 104 served by the one or more NE 102 associated with the CN 106.

The CN 106 may communicate with a packet data network over one or more backhaul links (e.g. via an S1, N2, or another network interface) . The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g. a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g. control information, data, and the like) between the UE 104 and the application server using the established session (e.g. the established PDU session) . The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g. one or more network functions of the CN 106) .

In the wireless communications system 100, the NEs 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g. time resources (e.g. symbols, slots, subframes, frames, or the like) or frequency resources (e.g. subcarriers, carriers) ) to perform various operations (e.g. wireless communications) . In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures) . The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g. μ=0) may be associated with a first subcarrier spacing (e.g. 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g. μ=0) associated with the first subcarrier spacing (e.g. 15 kHz) may utilize one slot per subframe. A second numerology (e.g. μ=1) may be associated with a second subcarrier spacing (e.g. 30 kHz) and a normal cyclic prefix. A third numerology (e.g. μ=2) may be associated with a third subcarrier spacing (e.g. 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g. μ=3) may be associated with a fourth subcarrier spacing (e.g. 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g. μ=4) may be associated with a fifth subcarrier spacing (e.g. 240 kHz) and a normal cyclic prefix.

A time interval of a resource (e.g. a communication resource) may be organized according to frames (also referred to as radio frames) . Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

Additionally or alternatively, a time interval of a resource (e.g. a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g. quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., μ=0, μ=1, μ=2, μ=3, μ=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g. quantity) of symbols (e.g. OFDM symbols) . In some implementations, the number (e.g. quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g. applicable for 60 kHz subcarrier spacing) , a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g. μ=0) associated with a first subcarrier spacing (e.g. 15 kHz) may be used interchangeably between subframes and slots.

In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz –7.125 GHz) , FR2 (24.25 GHz –52.6 GHz) , FR3 (7.125 GHz –24.25 GHz) , FR4 (52.6 GHz –114.25 GHz) , FR4a or FR4-1 (52.6 GHz –71 GHz) , and FR5 (114.25 GHz –300 GHz) . In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g. control information, data) . In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

FR1 may be associated with one or multiple numerologies (e.g. at least three numerologies) . For example, FR1 may be associated with a first numerology (e.g. μ=0) , which includes 15 kHz subcarrier spacing; a second numerology (e.g. μ=1) , which includes 30 kHz subcarrier spacing; and a third numerology (e.g. μ=2) , which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g. at least 2 numerologies) . For example, FR2 may be associated with a third numerology (e.g. μ=2) , which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g. μ=3) , which includes 120 kHz subcarrier spacing.

Figure 2 illustrates an example of a UE 200 in accordance with aspects of the present application. The UE 200 may include a processor 202, a memory 204, a controller 206, and a transceiver 208. The processor 202, the memory 204, the controller 206, or the transceiver 208, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present application as described herein. These components may be coupled (e.g. operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 202, the memory 204, the controller 206, or the transceiver 208, or various combinations or components thereof may be implemented in hardware (e.g. circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present application.

The processor 202 may include an intelligent hardware device (e.g. a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 202 may be configured to operate the memory 204. In some other implementations, the memory 204 may be integrated into the processor 202. The processor 202 may be configured to execute computer-readable instructions stored in the memory 204 to cause the UE 200 to perform various functions of the present application.

The memory 204 may include volatile or non-volatile memory. The memory 204 may store computer-readable, computer-executable code including instructions when executed by the processor 202 cause the UE 200 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 204 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 202 and the memory 204 coupled with the processor 202 may be configured to cause the UE 200 to perform one or more of the functions described herein (e.g. executing, by the processor 202, instructions stored in the memory 204) . For example, the processor 202 may support wireless communication at the UE 200 in accordance with examples as disclosed with respect to Figure 5. The UE 200 may be configured to support: a means for receiving a configuration including information of at least one event for an L1 measurement report; a means for evaluating whether the at least one event is fulfilled during a time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the time window; and a means for receiving another configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

The controller 206 may manage input and output signals for the UE 200. The controller 206 may also manage peripherals not integrated into the UE 200. In some implementations, the controller 206 may utilize an operating system such as or other operating systems. In some implementations, the controller 206 may be implemented as part of the processor 202.

In some implementations, the UE 200 may include at least one transceiver 208. In some other implementations, the UE 200 may have more than one transceiver 208. The transceiver 208 may represent a wireless transceiver. The transceiver 208 may include one or more receiver chains 210, one or more transmitter chains 212, or a combination thereof. The means for receiving abovementioned in the processor 202 or the means for transmitting in the processor 202 may be implemented via at least one transceiver 208.

A receiver chain 210 may be configured to receive signals (e.g. control information, data, packets) over a wireless medium. For example, the receiver chain 210 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 210 may include at least one amplifier (e.g. a low-noise amplifier (LNA) ) configured to amplify the received signal. The receiver chain 210 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 210 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

A transmitter chain 212 may be configured to generate and transmit signals (e.g. control information, data, packets) . The transmitter chain 212 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM) , frequency modulation (FM) , or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM) . The transmitter chain 212 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 212 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

Figure 3 illustrates an example of a processor 300 in accordance with aspects of the present application. The processor 300 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 300 may include a controller 302 configured to perform various operations in accordance with examples as described herein. The processor 300 may optionally include at least one memory 304, which may be, for example, an L1/L2/L3 cache. Additionally, or alternatively, the processor 300 may optionally include one or more arithmetic-logic units (ALUs) 306. One or more of these components may be in electronic communication or otherwise coupled (e.g. operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g. buses) .

The processor 300 may be a processor chipset and include a protocol stack (e.g. a software stack) executed by the processor chipset to perform various operations (e.g. receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g. memory local to or included in the processor chipset (e.g. the processor 300) or other memory (e.g. random access memory (RAM) , read-only memory (ROM) , dynamic RAM (DRAM) , synchronous dynamic RAM (SDRAM) , static RAM (SRAM) , ferroelectric RAM (FeRAM) , magnetic RAM (MRAM) , resistive RAM (RRAM) , flash memory, phase change memory (PCM) , and others) .

The controller 302 may be configured to manage and coordinate various operations (e.g. signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 300 to cause the processor 300 to support various operations in accordance with examples as described herein. For example, the controller 302 may operate as a control unit of the processor 300, generating control signals that manage the operation of various components of the processor 300. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

The controller 302 may be configured to fetch (e.g. obtain, retrieve, receive) instructions from the memory 304 and determine subsequent instruction (s) to be executed to cause the processor 300 to support various operations in accordance with examples as described herein. The controller 302 may be configured to track memory address of instructions associated with the memory 304. The controller 302 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 302 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 300 to cause the processor 300 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 302 may be configured to manage flow of data within the processor 300. The controller 302 may be configured to control transfer of data between registers, arithmetic logic units (ALUs) , and other functional units of the processor 300.

The memory 304 may include one or more caches (e.g. memory local to or included in the processor 300 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 304 may reside within or on a processor chipset (e.g. local to the processor 300) . In some other implementations, the memory 304 may reside external to the processor chipset (e.g. remote to the processor 300) .

The memory 304 may store computer-readable, computer-executable code including instructions that, when executed by the processor 300, cause the processor 300 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 302 and/or the processor 300 may be configured to execute computer-readable instructions stored in the memory 304 to cause the processor 300 to perform various functions. For example, the processor 300 and/or the controller 302 may be coupled with or to the memory 304, the processor 300, the controller 302, and the memory 304 may be configured to perform various functions described herein. In some examples, the processor 300 may include multiple processors and the memory 304 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

The one or more ALUs 306 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 306 may reside within or on a processor chipset (e.g. the processor 300) . In some other implementations, the one or more ALUs 306 may reside external to the processor chipset (e.g. the processor 300) . One or more ALUs 306 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 306 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 306 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 306 may support logical operations such as AND, OR, exclusive-OR (XOR) , not-OR (NOR) , and not-AND (NAND) , enabling the one or more ALUs 306 to handle conditional operations, comparisons, and bitwise operations.

The processor 300 may support wireless communication in accordance with examples as disclosed herein.

In some implementations, the processor 300 may be configured to support means for performing operations of a UE as described with respect to Figure 5. The processor 300 may be configured to or operable to support: a means for receiving a configuration including information of at least one event for an L1 measurement report; a means for evaluating whether the at least one event is fulfilled during a time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the time window; and a means for receiving another configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

In some implementations, the processor 300 may be configured to support means for performing operations of a BS as described with respect to Figure 6. The processor 300 may be configured to or operable to support: a means for receiving, from a UE, capability information indicating that the UE supports an event based L1 measurement report; a means for transmitting, to the UE, a configuration including information of at least one event for an L1 measurement report; and a means for transmitting, to the UE, another configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

It should be appreciated by persons skilled in the art that the components in exemplary processor 300 may be changed, for example, some of the components in exemplary processor 300 may be omitted or modified or new component (s) may be added to exemplary processor 300, without departing from the spirit and scope of the application. For example, in some embodiments, the processor 300 may not include the ALUs 306.

Figure 4 illustrates an example of a NE 400 in accordance with aspects of the present application. The NE 400 may include a processor 402, a memory 404, a controller 406, and a transceiver 408. The processor 402, the memory 404, the controller 406, or the transceiver 408, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present application as described herein. These components may be coupled (e.g. operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 402, the memory 404, the controller 406, or the transceiver 408, or various combinations or components thereof may be implemented in hardware (e.g. circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application- specific integrated circuit (ASIC) , or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present application.

The processor 402 may include an intelligent hardware device (e.g. a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 402 may be configured to operate the memory 404. In some other implementations, the memory 404 may be integrated into the processor 402. The processor 402 may be configured to execute computer-readable instructions stored in the memory 404 to cause the NE 400 to perform various functions of the present application.

The memory 404 may include volatile or non-volatile memory. The memory 404 may store computer-readable, computer-executable code including instructions when executed by the processor 402 cause the NE 400 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 404 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 402 and the memory 404 coupled with the processor 402 may be configured to cause the NE 400 to perform one or more of the functions described herein (e.g. executing, by the processor 402, instructions stored in the memory 404) . For example, the processor 402 may support wireless communication at the NE 400 in accordance with examples as disclosed herein.

In some implementations, the NE 400 may be a BS as described with respect to Figure 6. The NE 400 may be configured to support: a means for receiving, from a UE, capability information indicating that the UE supports an event based L1 measurement report; a means for transmitting, to the UE, a configuration including information of at least one event for an L1 measurement report; and a means for transmitting, to the UE, another configuration which is used to update at least one of: a current beam of a serving cell of the UE; or a set of beams of at least one candidate cell of the UE.

The controller 406 may manage input and output signals for the NE 400. The controller 406 may also manage peripherals not integrated into the NE 400. In some implementations, the controller 406 may utilize an operating system such as or other operating systems. In some implementations, the controller 406 may be implemented as part of the processor 402.

In some implementations, the NE 400 may include at least one transceiver 408. In some other implementations, the NE 400 may have more than one transceiver 408. The transceiver 408 may represent a wireless transceiver. The transceiver 408 may include one or more receiver chains 410, one or more transmitter chains 412, or a combination thereof. The means for receiving or the means for transmitting abovementioned in the processor 402 may be implemented via at least one transceiver 408.

A receiver chain 410 may be configured to receive signals (e.g. control information, data, packets) over a wireless medium. For example, the receiver chain 410 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 410 may include at least one amplifier (e.g. a low-noise amplifier (LNA) ) configured to amplify the received signal. The receiver chain 410 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 410 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

A transmitter chain 412 may be configured to generate and transmit signals (e.g. control information, data, packets) . The transmitter chain 412 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM) , frequency modulation (FM) , or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM) . The transmitter chain 412 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 412 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

It should be appreciated by persons skilled in the art that the components in exemplary NE 400 may be changed, for example, some of the components in exemplary NE 400 may be omitted or modified or new component (s) may be added to exemplary NE 400, without departing from the spirit and scope of the application. For example, in some embodiments, the NE 400 may not include the controller 406.

Figure 5 illustrates a flowchart related to an L1 event measurement report and conditional LTM in accordance with aspects of the present application. The operations of the method may be implemented by a UE as described herein. In some implementations, the UE may execute a set of instructions to control the function elements of the UE to perform the described functions. In some implementations, aspects of operations 502, 504 and 506 may be performed by UE 200 as described with reference to Figure 2. Each of 502, 504 and 506 may be performed in accordance with examples as described herein. Specific examples are described in the embodiments of Figures 7 and 8 as follows.

At 502, the method may include receiving, by a UE, a configuration (denoted as a first configuration) including information of at least one event for an L1 measurement report, for example from a BS (e.g. a MN or a SN) . In some implementations, the at least one event includes:

(1) a current beam of a serving cell of the UE becomes worse than a threshold, e.g. Event #A;

(2) any beam of at least one candidate cell becomes an amount of offset better than the current beam of the serving cell, e.g. Event #B;

(3) any beam of the at least one candidate cell becomes better than a threshold, e.g. Event #C; and/or

(4) the current beam of the serving cell becomes worse than a threshold and any beam of the at least one candidate cell becomes better than another threshold, e.g. Event #D.

In some implementations, the information of the at least one event (which is received at 502) includes at least one of the following:

(1) ID information of the at least one event, e.g. an event ID;

(2) one or more offsets for the at least one event, e.g. Ofn or Ocn;

(3) one or more hysteresis parameters for the at least one event, e.g. Hys;

(4) one or more thresholds for the at least one event, e.g. Thresh;

(5) one or more filter parameters for the at least one event; or

(6) a length of a time window (e.g. TTT) associated with the at least one event.

At 504, the method may include evaluating, by the UE, whether the at least one event is fulfilled during a time window (denoted as a first time window, e.g. TTT#1) . The L1 measurement report may be triggered once an entering condition for the at least one event is fulfilled during the first time window.

At 506, the method may include receiving, by the UE, another configuration (denoted as a second configuration) , for example from a BS (e.g. a MN) . In some embodiments, the second configuration is carried in DCI, a MAC CE, and/or an RRC reconfiguration message. For example, the second configuration may be used to update at least one of the following:

(1) a current beam of a serving cell of the UE. For example, the current beam may be a SSB index or a CSI-RS.

(2) a set of beams of at least one candidate cell of the UE. For example, a beam within the set of beams may be a SSB index or a CSI-RS.

In some implementations of the method, the UE may reset the first time window (e.g. may stop TTT #1) , if at least one of following conditions occurs according to the second configuration during the first time window (e.g. when TTT #1 is running) :

(1) the current beam of the serving cell is changed, e.g. the current beam is changed from beam #1 to beam #2;

(2) a measurement RS corresponding to the current beam of the serving cell is changed;

(3) a TCI state corresponding to the current beam of the serving cell is changed;

(4) the set of beams (e.g. a beam list) of the at least one candidate cell is updated;

(5) one or more beams within the set of beams of the at least one candidate cell are removed, if the one or more beams can meet at least one entering condition, e.g. in a case that "only one beam of a candidate cell meeting the entering condition while this beam is removed" ;

(6) a reception of a candidate cell TCI states activation MAC CE on the serving cell; or

(7) a reception of a candidate cell TCI states deactivation MAC CE on the serving cell.

In some implementations, the UE may maintain the first time window (e.g. may keep TTT #1 running) , if at least one of following conditions occurs according to the second configuration during the first time window (e.g. when TTT #1 is running) :

(1) the current beam of the serving cell is changed;

(3) a TCI state corresponding to the current beam of the serving cell is changed; or

(4) the set of beams of the at least one candidate cell is updated.

In some implementations of the method, the UE may receive a reconfiguration message (e.g. an RRC reconfigure message) including (1) an LTM candidate configuration associated with one or more LTM candidate cells and (2) a set of execution conditions corresponding to the one or more LTM candidate cells. Then, the UE may evaluate whether an execution condition within the set of execution conditions is fulfilled during a time window (denoted as a second time window, e.g. TTT #2) . In some embodiments, the UE may receive an LTM cell switch command (e.g. LTM command #1) associated with an LTM candidate cell (denoted as a first LTM candidate cell) within the one or more LTM candidate cells. The LTM cell switch command includes an early TA value (denoted as a first early TA value) and ID information of the first LTM candidate cell. For example, the LTM cell switch command is carried in an LTM cell switch command MAC CE.

In some implementations, after reception of the LTM cell switch command (e.g. LTM command #1) , the UE may prohibit to perform an LTM cell switch towards the first LTM candidate cell. For example, the UE may prohibit to apply the LTM candidate configuration associated with the first LTM candidate cell. That is, the UE is not expected to apply this LTM candidate configuration due to reception of the LTM cell switch command.

In some implementations, the UE may start a time alignment timer (TAT) for the first early TA value included in the LTM cell switch command (e.g. LTM command #1) .

In some implementations, the LTM cell switch command (e.g. LTM command #1) includes an activated TCI state associated with the first LTM candidate cell. In some embodiments, the UE may ignore the activated TCI state. In some other embodiments, the UE may store the activated TCI state and apply the activated TCI state when performing an LTM cell switch towards the first LTM candidate cell.

In some embodiments, once an execution condition corresponding to an LTM candidate cell (denoted as a second LTM candidate cell) within the one or more LTM candidate cells is fulfilled during the second time window (e.g. when TTT #2 is running) , the UE may trigger to perform an LTM cell switch towards the second LTM candidate cell and start an LTM timer (e.g. timer T304) for the LTM cell switch towards the second LTM candidate cell.

In some other embodiments, if the first early TA value associated with the first LTM candidate cell is still valid when the execution condition corresponding to the first LTM candidate cell is fulfilled, the UE may perform a RACH-less LTM cell switch towards the first LTM candidate cell by using the first early TA value.

In some other implementations of the method, the UE may receive a reconfiguration message (e.g. an RRC reconfiguration message) including (1) an LTM candidate configuration associated with one or more LTM candidate cells and (2) a set of execution conditions corresponding to the one or more LTM candidate cells. Then, the UE may evaluate whether an execution condition within the set of execution conditions is fulfilled during a time window (denoted as a third time window, e.g. TTT #3) . In some embodiments, the UE may receive a set of early TA values (denoted as a first set of early TA values) associated with the one or more LTM candidate cells and ID information of the one or more LTM candidate cells, and receive an LTM cell switch command (e.g. LTM command #2) associated with a LTM candidate cell (denoted as a third LTM candidate cell) within the one or more LTM candidate cells. For example, the LTM cell switch command is carried in an LTM cell switch command MAC CE.

For instance, the first set of early TA values and the ID information are carried in DCI, a MAC CE, and/or an RRC configuration.

In some implementations, the first set of early TA values and the ID information are received, by the UE from a source DU of a BS associated with the serving cell, before the execution condition within the set of execution conditions is fulfilled during the third time window (e.g. when TTT #3 is running) .

In some embodiments, if the LTM cell switch command (e.g. LTM command #2) includes an early TA value (denoted as a third early TA value) associated with the third LTM candidate cell, and if an early TA value (denoted as a second early TA value) associated with the third LTM candidate cell is provided in the first set of early TA values before the third early TA value is provided, the UE may perform a RACH-less LTM cell switch towards the third LTM candidate cell by using the third early TA value.

In some other embodiments, if the LTM cell switch command (e.g. LTM command #2) does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is still valid, the UE may perform a RACH-less LTM cell switch towards the third LTM candidate cell by using the second early TA value.

In some additional embodiments, if the LTM cell switch command (e.g. LTM command #2) does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is invalid, the UE may perform a RACH based LTM cell switch towards the third LTM candidate cell without using the second early TA value.

In some implementations of the method, the UE may stop evaluating the execution condition corresponding to the third LTM candidate cell, once the RACH-less LTM cell switch or the RACH based LTM cell switch towards the third LTM candidate cell is triggered.

It should be noted that the method described in Figure 5 describes possible implementations, and that the operations and the steps may be rearranged or otherwise eliminated or modified and that other implementations are possible, without departing from the spirit and scope of the application.

Figure 6 illustrates a flowchart related to an L1 event measurement report and conditional LTM in accordance with aspects of the present application. The operations of the method may be implemented by a network node as described herein. In some implementations, the network node may be a BS (e.g. a MN or a SN) , and may execute a set of instructions to control the function elements of the BS to perform the described functions. In some implementations, aspects of operations 602, 604 and 606 may be performed by NE 400 as described with reference to Figure 4. Each of 602, 604 and 606 may be performed in accordance with examples as described herein. Specific examples are described in the embodiments of Figures 7 and 8 as follows.

At 602, the method may include receiving, by a BS from a UE, capability information indicating that the UE supports an event based L1 measurement report.

At 604, the method may include transmitting, by the BS to the UE, a configuration (e.g. the first configuration in the embodiments of Figure 5) including information of at least one event for an L1 measurement report. The configuration may include the same or similar elements as those in the first configuration as described in the embodiments of Figure 5. The at least one event may include the same or similar elements as those in the at least one event as described in the embodiments of Figure 5, e.g. Event #A, Event #B, Event #C and/or Event #D.

At 606, the method may include transmitting, by the BS to the UE, another configuration (e.g. the second configuration in the embodiments of Figure 5) which is used to update at least one of: (1) a current beam of a serving cell of the UE; or (2) a set of beams of at least one candidate cell of the UE. This configuration may include the same or similar elements as those in the second configuration as described in the embodiments of Figure 5. For example, this configuration may be carried in DCI, a MAC CE, and/or an RRC reconfiguration message.

In some implementations, the current beam of the serving cell and/or the set of beams of the at least one candidate cell may be a SSB index or a CSI-RS.

In some implementations of the method, the BS may transmit, to the UE, a reconfiguration message (e.g. an RRC reconfiguration message) including (1) an LTM candidate configuration associated with one or more LTM candidate cells and (2) a set of execution conditions corresponding to the one or more LTM candidate cells. The BS may transmit, to the UE, an LTM cell switch command (e.g. LTM command #1 in the embodiments of Figure 5) associated with an LTM candidate cell (e.g. a first LTM candidate cell in the embodiments of Figure 5) within the one or more LTM candidate cells. The LTM cell switch command includes an early TA value (e.g. a first early TA value in the embodiments of Figure 5) and ID information of the first LTM candidate cell. For example, the LTM cell switch command is carried in an LTM cell switch command MAC CE.

In some implementations, after the LTM cell switch command (e.g. LTM command #1) is received by the UE, an LTM cell switch towards the first LTM candidate cell is prohibited to be performed at the UE. For example, the UE may prohibit to apply the LTM candidate configuration associated with the first LTM candidate cell. That is, the UE is not expected to apply this LTM candidate configuration due to reception of the LTM cell switch command.

For example, the LTM cell switch command (e.g. LTM command #1) includes an activated TCI state associated with the first LTM candidate cell. In some implementations, the activated TCI state can be ignored by the UE. In some other implementations, the activated TCI state can be applied by the UE when performing an LTM cell switch towards the first LTM candidate cell.

In some implementations of the method, the BS may transmit, to the UE, a reconfiguration message including (1) an LTM candidate configuration associated with one or more LTM candidate cells and (2) a set of execution conditions corresponding to the one or more LTM candidate cells. The BS may transmit, to the UE, a set of early TA values (e.g. a first set of early TA values in the embodiments of Figure 5) associated with the one or more LTM candidate cells and ID information of the one or more LTM candidate cells, and transmit, to the UE, an LTM cell switch command (e.g. LTM command #2 in the embodiments of Figure 5) associated with an LTM candidate cell (e.g. a third set of early TA values in the embodiments of Figure 5) within the one or more LTM candidate cells.

In some implementations, the first set of early TA values and the ID information are carried in DCI, a MAC CE, and/or an RRC configuration.

In some implementations of the method, the first set of early TA values and the ID information are transmitted, by a source DU of the BS associated with the serving cell, before the execution condition within the set of execution conditions is fulfilled during a corresponding time window.

In some embodiments, if the LTM cell switch command (e.g. LTM command #2) includes an early TA value (e.g. a third early TA value in the embodiments of Figure 5) associated with the third LTM candidate cell, and if an early TA value (e.g. a second early TA value in the embodiments of Figure 5) associated with the third LTM candidate cell is provided in the first set of early TA values before the third early TA value is provided, a RACH-less LTM cell switch towards the third LTM candidate cell can be performed by the UE using the third early TA value.

In some other embodiments, if the LTM cell switch command (e.g. LTM command #2) does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is still valid, a RACH-less LTM cell switch towards the third LTM candidate cell can be performed by the UE using the second early TA value.

In some additional embodiments, if the LTM cell switch command (e.g. LTM command #2) does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is invalid, a RACH based LTM cell switch towards the third LTM candidate cell can be performed by the UE without using the second early TA value.

In some implementations of the method, the BS includes a CU, a source DU which manages the serving cell, and at least one candidate DU which manages one or more LTM candidate cells. In some embodiments, the CU of the BS may determine to initiate condition based LTM mobility, and transmit a request to the at least one candidate DU. The request may include: (1) ID information of a target candidate cell within the one or more LTM candidate cells; and (2) information indicating that the request is associated with the condition based LTM mobility.

In some implementations, the CU of the BS may transmit to the source DU and the UE: (1) an LTM candidate configuration associated with the one or more LTM candidate cells and (2) a set of execution conditions corresponding to the one or more LTM candidate cells. The CU may transmit, to the source DU and the UE, information indicating that "an LTM cell switch command associated with an LTM candidate cell within the one or more LTM candidate cells is allowed to be transmitted. "

In some embodiments, the CU of the BS may decide whether the LTM cell switch command can be used to trigger an LTM cell switch towards the LTM candidate cell.

It should be noted that the method described in Figure 6 describes possible implementations, and that the operations and the steps may be rearranged or otherwise eliminated or modified and that other implementations are possible, without departing from the spirit and scope of the application.

Figure 7 illustrates a schematic diagram of an L1 event measurement report and conditional LTM in accordance with aspects of the present application. Details described in all other embodiments of the present application are applicable for the embodiments shown in Figure 7.

In 701, a UE accesses a network node via MCG only or Dual-connectivity (DC) including MCG and SCG. Namely, the UE may access a MN and a SN shown in Figure 7 via DC.

In some embodiments of 701, the UE may report the UE capability to the network node (e.g. the MN) if receiving the enquiry from the MN. For example, the UE may report:

(1) information to indicate whether the UE supports an event based L1 measurement report;

(2) information to indicate which event the UE supports for an L1 measurement report. In an embodiment, the event includes at least one of the following:

- Event #A: Beam (s) of a serving cell becomes worse than an absolute threshold; the Entering conditions and Leaving conditions defined for Event #1 may be applied for Event #A.

- Event #B: Beam (s) of a candidate cell becomes amount of offset better than the beam (s) of the serving cell; the Entering conditions and Leaving conditions defined for Event #2 may be applied for Event #B.

- Event #C: Beam (s) of a candidate cell becomes better than an absolute threshold; the Entering conditions and Leaving conditions defined for Event #3 may be applied for Event #C.

- Event #D: Beam (s) of a serving cell becomes worse than absolute threshold AND Beam (s) of a candidate cell becomes better than another absolute threshold. The Entering conditions and Leaving conditions defined for Event #4 may be applied for Event #D.

(3) information to indicate whether to support an event based L1 measurement report based on CSI-RS; and/or

(4) information to indicate whether to support an event based L1 measurement report based on SSB.

In some embodiments of 701, the UE may receive a configuration related to L1 measurement report (e.g. the first configuration) from the MN. If DC is configured, the UE may receive the configuration related to L1 measurement report from both the MN and the SN. The configuration from the SN is configured for SCG LTM purpose.

In 702, the network node (e.g. the MN) transmits an RRC reconfiguration message including at least the L1 measurement report. For example, the RRC reconfiguration message includes at least one of the following:

(1) An indication to indicate which event is used for triggering a measurement report, for example, e.g., the indication is an event ID.

(2) An indication to indicate whether an L1 measurement report can be triggered or not once a leaving condition is met.

(3) An indication to indicate whether an L1 measurement report is periodic once an L1 measurement report is triggered.

(4) An indication to indicate the number of L1 measurement report (s) if multiple L1 measurement reports are supported.

In 703, the UE starts to evaluate the event according to the configuration received in 702.

For example, if Event #B and TTT are configured to the UE, the UE may stars TTT when an entering condition of Event #B is met. The UE may continue evaluating whether the entering condition is met during TTT. In Event #B, the beam of the serving cell of the UE is the current beam which is indicated by TCI state. If the current beam of the serving cell is changed, e.g., due to receiving a configuration in DCI, a MAC CE, and/or an RRC reconfiguration (e.g. the second configuration) , the UE's behavior regarding TTT for Event #B may be different in different embodiments, i.e. Option #1, and Option #2:

(1) Option #1: the UE may stop the running TTT, if at least one of following conditions occurs, e.g. due to DCI, a MAC CE, and/or RRC reconfiguration:

- if the current beam of the serving cell is changed;

- if a measurement RS corresponding to the current beam is changed; or

- if the current beam or the TCI state corresponding to the current beam is changed.

(2) Option #2: the UE may keep TTT running if at least one of following conditions occurs, e.g. due to DCI, a MAC CE, and/or RRC reconfiguration:

- if the current beam of the serving cell is changed;

- if measurement RS corresponding to the current beam is changed; or

For example, regarding Event #B, if any beam of the candidate cell can meet the entering condition, the entering condition will be considered as met at that instance. If the entering condition is met within TTT, the condition is considered by the UE as satisfied. Then, the L1 measurement report will be triggered. If the beam configuration of a candidate cell is changed, e.g., due to DCI, a MAC CE and/or RRC reconfiguration, the UE's behavior regarding TTT for Event #B may be different in different embodiments, i.e. Option #X, and Option #Y:

(1) Option #X: the UE may stop the running TTT only if one of the conditions occurs:

- a set of beams of the at least one candidate cell (e.g. a beam list) is updated. The beam list may include SSB or CSI-RS;

- one or more beams of at least one candidate cell meeting the entering condition are removed;

- only one beam of at least one candidate cell meets the entering condition but this beam is removed;

- the UE receives a candidate Cell TCI States Activation MAC CE on the serving cell; or

- the UE receives a candidate Cell TCI States Deactivation MAC CE on the serving cell.

(2) Option #Y: the UE may keep all TTT running if the beam configuration of at least one candidate cell is changed, e.g. due to an RRC reconfiguration or a MAC CE.

Similarly, for Event #A, Event #C, and Event #D, the UE's behavior regarding TTT for any of these events may be different in different embodiments, i.e. Option #1, and Option #2, Option #X, or Option #Y may be performed for Event #A, Event #C, or Event #D in different embodiments.

In 704, the UE is triggered to report the L1 measurement results if the entering condition of the event is met within TTT. The UE may transmit a MAC CE which includes the L1 measurement report to the network node. For example, the MAC CE includes beam ID information and the corresponding beam quality.

In 705, after the network node receives the L1 measurement report, the network node will decide whether to trigger cell switch towards a candidate cell, e.g. an LTM cell switch.

Figure 8 illustrates a schematic diagrams of an L1 event measurement report and conditional LTM in accordance with aspects of the present application. Details described in all other embodiments of the present application are applicable for the embodiments shown in Figure 8.

Following text describes different embodiments of Figure 8 in different cases, i.e. Embodiment 1 and Embodiment 2.

Embodiment 1

In 801, a UE accesses a network node via MCG only or DC including MCG and SCG. Namely, the UE may access a MN and a SN shown in Figure 8 via DC.

In some embodiments of 801, the UE may report the UE capability to the network node (e.g. the MN) if receiving the enquiry from the MN. For example, the UE may report at least one of the following at 801:

(1) information to indicate whether the UE supports condition based LTM;

(2) information to indicate whether the UE supports condition based MCG LTM;

(3) information to indicate whether the UE supports condition based Intra-CU MCG LTM;

(4) information to indicate whether the UE supports condition based Inter-CU MCG LTM;

(5) information to indicate whether the UE supports condition based SCG LTM;

(6) information to indicate whether the UE supports condition based Intra-CU SCG LTM; or

(7) information to indicate whether the UE supports condition based Inter-CU SCG LTM.

In 802, the network node (i.e. the serving gNB, e.g. the MN or the SN) transmits a reconfiguration message (e.g. an RRC reconfiguration message) including an LTM candidate configuration and a set of execution conditions corresponding to one or more LTM candidate cells to the UE.

In some embodiments, the serving gNB (e.g. the MN or the SN) includes a CU, a source DU managing the serving cell, and at least one candidate DU managing one or more LTM candidate cells. The source CU of the serving gNB (i.e.gNB-CU) determines to initiate condition based LTM mobility. The gNB-CU sends a request message, e.g. a UE CONTEXT SETUP REQUEST message, to at least one candidate DU (e.g. candidate gNB-DU) , including the one or more target candidate cells. The request for RACH resource for early TA acquisition may also be included in the request message transmitted to the candidate gNB-DU. In addition, an indication for indicating that the request message is associated with condition based LTM may be included in request message.

In some embodiments, if the candidate gNB-DU decides to accept the request of LTM configuration related to a candidate cell, the candidate gNB-DU may respond to the gNB-CU including the RRC configuration for the accepted one or more target candidate cells. The response message could be with a UE CONTEXT SETUP RESPONSE message. A RACH resource for early TA acquisition may be included in the response message transmitted to the gNB-CU.

In some embodiments, the gNB-CU will transmit the configuration to the source DU and the UE. The gNB-CU may transmit the configuration, e.g. a RACH resource for early TA acquisition, to the source DU. In an embodiment, another LTM command is allowed to be transmitted for this condition based LTM candidate cell. In some implementation, whether an LTM command can be used to trigger LTM cell switch towards this condition based LTM candidate cell may be decided by the gNB-CU. The gNB-CU will generate an RRC reconfiguration message based on the configuration from the candidate cell and may transmit the RRC reconfiguration message to the UE via the source DU. For example, the RRC reconfiguration message includes (1) an LTM candidate configuration associated with one or more condition based LTM candidate cells and/or (2) a RACH resource for early TA acquisition.

In some embodiments, the UE receives an RRC reconfiguration message associated with one or more condition based LTM candidate cells. The UE receives a physical downlink control channel (PDCCH) order for triggering a timing advance (TA) acquisition to a particular candidate cell. The UE may transmit the preamble for TA acquisition to the candidate cell. If the candidate cell or the DU which manages the candidate cell can calculate an early TA value based on the received preamble, the candidate cell or the DU may transmit, to the source DU via the CU, the early TA value and at least one of: the preamble and RACH occasion, a beam indication, a UE ID, a RA-RNTI, a target cell ID, a TCI State index for the target Cell and etc.

In some embodiments, the MN transmits a configuration for the LTM candidate configuration for a PCell change and the corresponding one or more execution conditions. In some other embodiments, the MN or the SN transmits the configuration for the LTM candidate configuration for PSCell change and the corresponding one or more execution conditions.

In some embodiments, the following information may be included in the RRC reconfiguration message:

(1) an LTM candidate configuration for PCell change or MCG change, and one or more execution conditions corresponding to one or more LTM candidate cells for at least one of the following events:

- Condition Event LTM#1: Beam (s) of a serving cell becomes worse than an absolute threshold; the Entering conditions and Leaving conditions defined for Event #1 may be applied for Condition Event LTM#1.

- Condition Event LTM#2: Beam (s) of a candidate cell becomes amount of offset better than beam (s) of a serving cell; the Entering conditions and Leaving conditions defined for Event #2 may be applied for Condition Event LTM#2.

- Condition Event LTM#3: Beam (s) of a candidate cell becomes better than an absolute threshold; the Entering conditions and Leaving conditions defined for Event #3 may be applied for Condition Event LTM#3.

- Condition Event LTM#4: Beam (s) of a serving cell becomes worse than an absolute threshold AND Beam (s) of a candidate cell becomes better than another absolute threshold; the Entering conditions and Leaving conditions defined for Event #4 may be applied for Condition Event LTM#4.

(2) An LTM candidate configuration for PSCell change or SCG change, and one or more execution conditions corresponding to one or more LTM candidate cells for at least one of the following events:

In 803, after the UE receives the configuration for LTM candidate configuration for PCell change or PSCell change and the one or more execution conditions corresponding to one or more LTM candidate cells, the UE starts to evaluate the execution conditions.

- In some embodiments, LTM candidate ID information may be included in the RRC reconfiguration message, to represent this LTM candidate cell.

- In some embodiments, the UE receives the RRC reconfiguration message including an LTM candidate configuration and the corresponding one or more execution conditions, but the UE is not expected to apply this LTM candidate configuration due to reception of an LTM cell switch command MAC CE.

In 804, the UE receives an LTM cell switch command MAC CE (e.g. LTM command #1) associated with an LTM candidate cell (e.g. the first LTM candidate cell) including an early TA value (e.g. the first early TA value) and ID information of this LTM candidate cell.

Some embodiments assume that this LTM cell switch command MAC CE cannot be used to trigger cell switching towards a condition based LTM candidate cell. In these embodiments, the LTM command MAC CE can be reused for early TA value transmission. The UE will not execute LTM cell switch if the UE receives the LTM cell switch command MAC CE referring to a condition based LTM candidate cell.

In some embodiments, the LTM cell switch command MAC CE may include an activated TCI state. In an embodiment, the UE may ignore or discard the field for activated TCI state. In another embodiment, the UE may store the activated TCI state and apply the activated TCI state once executing LTM cell switch towards this LTM candidate cell.

In some embodiments, the UE will start TAT for this received early TA value in the LTM cell switch command MAC CE that is associated with a condition based LTM candidate cell.

In 805, once the execution condition for the condition based LTM candidate cell is met, the UE is triggered to perform LTM cell switch towards this LTM candidate cell and starts a LTM timer (e.g. T304) for this LTM cell switch. In some embodiments, if the early TA value is still valid, the UE performs RACH-less LTM cell switch based on this early TA value.

Embodiment 2

(1) information to indicate whether the UE supports condition based LTM;

(2) information to indicate whether the UE supports condition based MCG LTM;

(5) information to indicate whether the UE supports condition based SCG LTM;

In some embodiments, the gNB-CU will transmit the configuration to the source DU and the UE. The gNB-CU may transmit the configuration, e.g. RACH resource for early TA acquisition, to the source DU. In an embodiment, another LTM command is allowed to be transmitted for this condition based LTM candidate cell. In some implementation, whether an LTM command can be used to trigger LTM cell switch towards this condition based LTM candidate cell may be decided by the gNB-CU. The gNB-CU will generate an RRC reconfiguration message based on the configuration from the candidate cell and may transmit the RRC reconfiguration message to the UE via the source DU. For example, the RRC reconfiguration message includes (1) an LTM candidate configuration associated with one or more condition based LTM candidate cells and/or (2) a RACH resource for early TA acquisition.

In some embodiments, the UE receives an RRC reconfiguration message associated with one or more condition based LTM candidate cells. The UE receives a PDCCH order for triggering a TA acquisition to a particular candidate cell. The UE may transmit the preamble for TA acquisition to the candidate cell. If the candidate cell or the DU which manages the candidate cell can calculate an early TA value based on the received preamble, the candidate cell or the DU may transmit, to the source DU via the CU, the early TA value and at least one of: the preamble and RACH occasion, a beam indication, a UE ID, a RA-RNTI, a target cell ID, a TCI State index for the target Cell and etc. The source DU may transmit the early TA value via a new MAC CE to the UE before the UE executes the LTM cell switch.

(2) An LTM candidate configuration for PSCell change or SCG change, and one or more execution conditions corresponding to one or more LTM candidate cells for at least one of the following events.

- Condition Event LTM#1: Beam (s) of a serving cell becomes worse than an absolute threshold; the Entering conditions and Leaving conditions defined for Event #1 may be applied for Condition Event LTM#1

In 803, after the UE receives the configuration for LTM candidate configuration for PCell change or PSCell change and the corresponding condition related to a candidate cell, the UE starts to evaluate the condition.

In 804, the UE receives an LTM cell switch command MAC CE (e.g. LTM command #2) including an early TA value (e.g. the third early TA value) .

Some embodiments assume that the LTM command MAC CE can be used to trigger cell switching towards a condition based LTM candidate cell. If the LTM cell switch command MAC CE can be used to execute condition based LTM mobility, a set of early TA values (e.g. the first set of early TA values) associated with one or more LTM candidate cells could be transmitted, e.g. in a new MAC CE, a new DCI or an new RRC configuration (that is different from the LTM cell switch command MAC CE) . For example, the following two cases focus on a new MAC CE (different from the LTM cell switch command MAC CE) to carry the set of early TA values. A Source DU may transmit the set of early TA values via a new MAC CE to the UE before the execution condition of LTM cell switch is met.

For example, different operations may be performed in different embodiments, i.e. Case #1, and Case #2.

- Case #1: After receiving a MAC CE including a set of early TA values (e.g. the first set of early TA values) and the corresponding cell ID, the UE may store an early TA values associated with an LTM candidate cell (e.g. cell #1) . The cell ID corresponding to the LTM candidate cell could be a target configuration ID or an LTM candidate ID. Then, if the UE receives an LTM cell switch command MAC CE including an early TA value (e.g. the third early TA value) for the same LTM candidate cell (e.g. cell #1) , the UE should use the early TA value (e.g. the third early TA value) included in LTM cell switch command MAC CE for this RACH-less cell switch.

- Case #2: After receiving a MAC CE including a set of early TA values (e.g. the first set of early TA values) and the corresponding cell ID, the UE may store an early TA value associated with an LTM candidate cell (e.g. cell #2) . The cell ID could be a target configuration ID or an LTM candidate ID. Then, if the UE receives an LTE cell switch command MAC CE without an early TA value for the same LTM candidate cell (e.g. cell #2) , the UE may perform any of the following operations:

- The UE may use an early TA value (e.g. for cell #2) included in the set of early TA values (e.g. the first set of early TA values) of the previously received MAC CE, if the early TA value is still valid.

- The UE may perform a RACH based LTM cell switch without using an early TA value.

- The UE may stop evaluating the execution condition for this LTM candidate cell (e.g. cell #2) , once LTM cell switch towards the LTM candidate cell (e.g. cell #2) is triggered.

The description herein is provided to enable a person having ordinary skill in the art to make or use the application. Various modifications to the application will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the application. Thus, the application is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A user equipment (UE) , comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to cause the UE to:

receive a first configuration including information of at least one event for a layer-1 (L1) measurement report;

evaluate whether the at least one event is fulfilled during a first time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the first time window; and

receive a second configuration which is used to update at least one of:

a current beam of a serving cell of the UE; or

a set of beams of at least one candidate cell of the UE.
The UE of claim 1, wherein the at least one event includes at least one of the following:

a current beam of a serving cell of the UE becomes worse than a first threshold;

any beam of at least one candidate cell becomes an amount of offset better than the current beam of the serving cell;

any beam of the at least one candidate cell becomes better than a second threshold; or

the current beam of the serving cell becomes worse than a third threshold and any beam of the at least one candidate cell becomes better than a fourth threshold, and

wherein the information of the at least one event includes at least one of the following:

identifier (ID) information of the at least one event;

one or more offsets for the at least one event;

one or more hysteresis parameters for the at least one event;

one or more thresholds for the at least one event;

one or more filter parameters for the at least one event; or

a length of a time window associated with the at least one event.
The UE of claim 1, wherein the second configuration is carried in at least one of the following:

downlink control information (DCI) ;

a medium access control (MAC) control element (CE) ; or

a radio resource control (RRC) reconfiguration message.
The UE of claim 1, wherein at least one of the current beam of the serving cell or the set of beams of the at least one candidate cell is:

a synchronization signal block (SSB) index; or

a channel state information reference signal (CSI-RS) .
The UE of claim 1, wherein the at least one processor is further configured to cause the UE to reset the first time window, if at least one of following conditions occurs according to the second configuration during the first time window:

the current beam of the serving cell is changed;

a measurement reference signal (RS) corresponding to the current beam of the serving cell is changed;

a transmission configuration indicator (TCI) state corresponding to the current beam of the serving cell is changed;

the set of beams of the at least one candidate cell is updated;

one or more beams within the set of beams of the at least one candidate cell are removed, if the one or more beams can meet at least one entering condition;

a reception of a candidate cell TCI states activation MAC CE on the serving cell; or

a reception of a candidate cell TCI states deactivation MAC CE on the serving cell.
The UE of claim 1, wherein the at least one processor is further configured to cause the UE to maintain the first time window, if at least one of following conditions occurs according to the second configuration during the first time window:

the current beam of the serving cell is changed;

a measurement reference signal (RS) corresponding to the current beam of the serving cell is changed;

a transmission configuration indicator (TCI) state corresponding to the current beam of the serving cell is changed; or

the set of beams of the at least one candidate cell is updated.
The UE of claim 1, wherein the at least one processor is further configured to cause the UE to:

receive a reconfiguration message including an L1/L2-Triggered Mobility (LTM) candidate configuration associated with one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells;

evaluate whether an execution condition within the set of execution conditions is fulfilled during a second time window; and

receive an LTM cell switch command associated with a first LTM candidate cell within the one or more LTM candidate cells, wherein the LTM cell switch command includes a first early timing advance (TA) value and identifier (ID) information of the first LTM candidate cell.
The UE of claim 7, wherein after reception of the LTM cell switch command, the at least one processor is further configured to cause the UE to prohibit to perform an LTM cell switch towards the first LTM candidate cell.
The UE of claim 7 or claim 8, wherein the at least one processor is further configured to cause the UE to start a time alignment timer (TAT) for the first early TA value included in the LTM cell switch command.
The UE of claim 7 or claim 8, wherein the LTM cell switch command includes an activated TCI state associated with the first LTM candidate cell, and the at least one processor is further configured to cause the UE to:

ignore the activated TCI state; or

store the activated TCI state and apply the activated TCI state when performing an LTM cell switch towards the first LTM candidate cell.
The UE of claim 7 or claim 8, wherein the at least one processor is further configured to cause the UE to:

once an execution condition corresponding to a second LTM candidate cell within the one or more LTM candidate cells is fulfilled during the second time window, trigger to perform an LTM cell switch towards the second LTM candidate cell and start an LTM timer for the LTM cell switch; and

if the first early TA value associated with the first LTM candidate cell is still valid when the execution condition corresponding to the first LTM candidate cell is fulfilled, perform a random access channel (RACH) -less LTM cell switch towards the first LTM candidate cell by using the first early TA value.
The UE of claim 1, wherein the at least one processor is further configured to cause the UE to:

receive a reconfiguration message including an L1/L2-Triggered Mobility (LTM) candidate configuration associated with one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells;

evaluate whether an execution condition within the set of execution conditions is fulfilled during a third time window;

receive a first set of early timing advance (TA) values associated with the one or more LTM candidate cells and identifier (ID) information of the one or more LTM candidate cells; and

receive an LTM cell switch command associated with a third LTM candidate cell within the one or more LTM candidate cells.
The UE of claim 12, wherein the first set of early TA values and the ID information are carried in at least one of the following:

downlink control information (DCI) ;

a medium access control (MAC) control element (CE) ; or

a radio resource control (RRC) configuration.
The UE of claim 12, wherein the first set of early TA values and the ID information are received from a source distributed units (DU) of a base station (BS) associated with the serving cell before the execution condition within the set of execution conditions is fulfilled during the third time window.
The UE of claim 12, wherein the at least one processor is further configured to cause the UE to:

if the LTM cell switch command includes a third early TA value associated with the third LTM candidate cell, and if a second early TA value associated with the third LTM candidate cell is provided in the first set of early TA values before the third early TA value is provided, perform a random access channel (RACH) -less LTM cell switch towards the third LTM candidate cell by using the third early TA value; or

if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is still valid, perform a RACH-less LTM cell switch towards the third LTM candidate cell by using the second early TA value; or

if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is invalid, perform a RACH based LTM cell switch towards the third LTM candidate cell without using the second early TA value.
The UE of claim 15, wherein the at least one processor is further configured to cause the UE to stop evaluating the execution condition corresponding to the third LTM candidate cell, once the RACH-less LTM cell switch or the RACH based LTM cell switch towards the third LTM candidate cell is triggered.
A base station (BS) , comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to cause the BS to:

receive, from a user equipment (UE) , capability information indicating that the UE supports an event based layer-1 (L1) measurement report;

transmit, to the UE, a first configuration including information of at least one event for an L1 measurement report; and

transmit, to the UE, a second configuration which is used to update at least one of:

a current beam of a serving cell of the UE; or

a set of beams of at least one candidate cell of the UE.
The BS of claim 17, wherein the at least one processor is further configured to cause the BS to:

transmit, to the UE, a reconfiguration message including an L1/L2-Triggered Mobility (LTM) candidate configuration associated with one or more LTM candidate cells and a set of execution conditions corresponding to the one or more LTM candidate cells;

transmit, to the UE, a first set of early timing advance (TA) values associated with the one or more LTM candidate cells and identifier (ID) information of the one or more LTM candidate cells; and

transmit, to the UE, an LTM cell switch command associated with a third LTM candidate cell within the one or more LTM candidate cells.
The BS of claim 18, wherein:

if the LTM cell switch command includes a third early TA value associated with the third LTM candidate cell, and if a second early TA value associated with the third LTM candidate cell is provided in the first set of early TA values before the third early TA value is provided, a random access channel (RACH) -less LTM cell switch towards the third LTM candidate cell can be performed by the UE using the third early TA value; or

if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is still valid, a RACH-less LTM cell switch towards the third LTM candidate cell can be performed by the UE using the second early TA value; or

if the LTM cell switch command does not include an early TA value, and if the second early TA value associated with the third LTM candidate cell is invalid, a RACH based LTM cell switch towards the third LTM candidate cell can be performed by the UE without using the second early TA value.
A processor of a user equipment (UE) for wireless communication, comprising:

at least one controller coupled with at least one memory and configured to cause the processor to:

receive a first configuration including information of at least one event for a layer-1 (L1) measurement report;

evaluate whether the at least one event is fulfilled during a first time window, wherein the L1 measurement report is triggered once an entering condition for the at least one event is fulfilled during the first time window; and

receive a second configuration which is used to update at least one of:

a current beam of a serving cell of the UE; or

a set of beams of at least one candidate cell of the UE.