Timer-based conditional switching events in terrestrial networks

Abstract

A method for a user equipment (UE) is provided. The UE receives, from a base station (BS), at least one conditional switching (CHO) command including an Ax event condition and a Tx event condition. The Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition. The UE evaluates both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied. In response to determining that the Ax event condition or the Tx event condition is satisfied, the UE determines a triggering cell for performing CHO.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communication systems, and more particularly to a timer-based conditional handover (CHO) event in a terrestrial network (TN). Background Art

[0002] Wireless mobile communication technologies use various standards and protocols to transmit data between base stations and wireless mobile devices. Wireless communication system standards and protocols may include, but are not limited to, 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE); fifth generation (5G) 3GPP New Radio (NR) standards; and technologies above 5G. In a fifth generation (5G) wireless radio access network (RAN), a base station may include a RAN node, such as a 5G node, a New Radio (NR) node, or a gNode B (gNB), which communicates with wireless communication devices (also known as user equipment (UE)). Summary of the invention

[0003] According to an aspect of the present disclosure, a method for a user equipment (UE) is provided, the method comprising: receiving at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; and determining a trigger cell for performing CHO in response to determining that the Ax event condition or the Tx event condition is satisfied.

[0004] According to an aspect of the present disclosure, a device for a UE is provided, the device including one or more processors, the one or more processors being configured to perform operations including the following: receiving at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; and determining a trigger cell for performing CHO in response to determining that the Ax event condition or the Tx event condition is satisfied.

[0005] According to an aspect of the present disclosure, there is provided a computer-readable medium having a computer program stored thereon, which, when executed by one or more processors, causes the one or more processors to perform operations including the following: receiving at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; and determining a trigger cell for performing CHO in response to determining that the Ax event condition or the Tx event condition is satisfied. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Features and advantages of the present disclosure will be apparent from the following detailed description taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the present disclosure.

[0007] Figure 1 is a block diagram of a system including a base station and a user equipment (UE) according to some embodiments.

[0008] Figure 2 A flow chart of an exemplary method for a UE according to some embodiments is illustrated.

[0009] Figure 3 An exemplary diagram illustrating a T1 event condition according to some embodiments.

[0010] Figure 4A An exemplary diagram illustrating T2 event conditions according to some embodiments.

[0011] Figure 4B Another exemplary diagram illustrating a T2 event condition according to some embodiments.

[0012] Figure 5A An exemplary diagram illustrating T3 event conditions according to some embodiments.

[0013] Figure 5B Another exemplary diagram illustrating a T3 event condition according to some embodiments.

[0014] Figure 6 A flow chart of an exemplary method for a base station according to some embodiments is illustrated.

[0015] Figure 7 An exemplary block diagram of an apparatus for a UE according to some embodiments is illustrated.

[0016] Figure 8 An exemplary block diagram of an apparatus for a base station according to some embodiments is illustrated.

[0017] Fig. 9 Example components of an apparatus according to some embodiments are illustrated.

[0018] Fig.10 Example interfaces for baseband circuitry according to some embodiments are illustrated.

[0019] Fig.11 Components according to some embodiments are illustrated.

[0020] Fig.12 The architecture of a wireless network according to some embodiments is illustrated. DETAILED DESCRIPTION

[0021] In the present disclosure, a "base station" may include a RAN node such as an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (also commonly denoted as an evolved Node B, an enhanced Node B, an eNodeB, or an eNB) and / or a Radio Network Controller (RNC) and / or a 5G node, a New Radio (NR) node, or a gNode B (gNB), which communicates with a wireless communication device also referred to as a user equipment (UE). Although some examples may be described with reference to any of an E-UTRAN Node B, an eNB, an RNC, and / or a gNB, such a device may be replaced with any type of base station.

[0022] In NR Release 17, the T1 event condition has been introduced into the conditional handover (CHO) for non-terrestrial networks (NTN). In the scenario of NTN, the T1 event condition must be configured together with any one of the CHO events A3-A5, and the CHO procedure can be performed only when one of the CHO events A3-A5 is met between the timing T1 threshold and T2 (T1 threshold plus duration). That is, the CHO procedure can be performed only when both the Ax event condition and the T1 event condition are met. For terrestrial networks (TN), timer-based CHO events aimed at improving the mobility of UEs may have attracted attention and require further discussion.

[0023] In the technology related to conditional handover (CHO), time-based trigger conditions have been introduced for NTN. Since the global navigation satellite system (GNSS) is always equipped in the NTN UE, the NTN UE can obtain accurate coordinated universal time (UTC) time via the GNSS. The NTN UE receives the Ax event condition and the T1 event condition from the base station, and initiates the CHO procedure when both the Ax event condition and the T1 event condition are met.

[0024] However, in the TN scenario, some UEs do not support GNSS. Such UEs (e.g., Network Energy Saving (NES) or Integrated Access and Backhaul (IAB) UEs that do not support GNSS) may not be able to obtain accurate UTC to correctly evaluate whether the time-based trigger condition is met. Therefore, the time-based trigger condition cannot be implemented in the case of TN. In addition, the CHO condition that satisfies both the Ax event condition and the T1 event condition may be too strict for NES UEs or IAB UEs. For UEs that do not support GNSS in the case of TN, relaxed CHO conditions need to be considered and introduced.

[0025] To achieve this goal, a timer-based CHO event in a TN is provided by the present disclosure. Various aspects of the present disclosure will be described below in conjunction with the accompanying drawings.

[0026] Figure 1 is a block diagram of a system including a base station and a UE according to some embodiments. Figure 1 A wireless network 100 according to some embodiments is illustrated. The wireless network 100 includes a UE 101 and a base station 150 connected via an air interface 190. In some embodiments, the base station 150 may be a mobile base station, such as a mobile IAB node.

[0027] UE 101 and any other UE in the system may be, for example, a laptop computer, a smart phone, a tablet computer, a printer, a machine type device, such as a smart meter or a dedicated device for healthcare monitoring, remote safety monitoring, an intelligent transportation system, or any other wireless device with or without a user interface. Base station 150 provides network connectivity to a wider network (not shown) to UE 101 via an air interface 190 in a base station service area provided by base station 150. In some embodiments, such a wider network may be a wide area network operated by a cellular network provider, or may be the Internet. Each base station service area associated with base station 150 is supported by an antenna integrated with base station 150. The service area is divided into a plurality of sectors associated with certain antennas. Such sectors may be physically associated with fixed antennas, or may be assigned to a physical area with a tunable antenna or antenna setting that may be adjusted in a beamforming process for directing signals to a particular sector. For example, one embodiment of the base station 150 includes three sectors, each sector covering a 120 degree area, with antenna arrays pointed toward each sector to provide 360 ​​degree coverage around the base station 150 .

[0028] UE 101 includes a control circuit 105 coupled to a transmission circuit 110 and a receiving circuit 115. The transmission circuit 110 and the receiving circuit 115 may each be coupled to one or more antennas. The control circuit 105 may be adapted to perform operations associated with machine type communication (MTC). In some embodiments, the control circuit 105 of UE 101 may perform calculations or may initiate measurements associated with the air interface 190 to determine the channel quality of the available connection to the base station 150. These calculations may be performed in conjunction with the control circuit 155 of the base station 150. The transmission circuit 110 and the receiving circuit 115 may be adapted to transmit and receive data, respectively. The control circuit 105 may be adapted to or configured to perform various operations, such as various operations related to the UE described elsewhere in this disclosure. The transmission circuit 110 may transmit multiple multiplexed uplink physical channels. The multiple uplink physical channels may be multiplexed according to time division multiplexing (TDM) or frequency division multiplexing (FDM). The transmission circuit 110 may be configured to receive block data from the control circuit 105 for transmission across the air interface 190. Similarly, the reception circuit 115 may receive a plurality of multiplexed downlink physical channels from the air interface 190 and relay these physical channels to the control circuit 105. The uplink and downlink physical channels may be multiplexed according to TDM or FDM. The transmission circuit 110 and the reception circuit 115 may transmit and receive control data and content data (e.g., messages, images, videos, etc.) structured within data blocks carried by the physical channels.

[0029] Figure 1 Also illustrated is a base station 150 according to various embodiments. The base station 150 circuitry may include a control circuit 155 coupled to a transmission circuit 160 and a reception circuit 165. The transmission circuit 160 and the reception circuit 165 may each be coupled to one or more antennas that may be used to enable communication via an air interface 190.

[0030] The control circuit 155 may be adapted to perform operations associated with MTC. The transmission circuit 160 and the reception circuit 165 may be adapted to transmit and receive data, respectively, within a narrow system bandwidth that is narrower than a standard bandwidth for personal communications. In some embodiments, for example, the transmission bandwidth may be set to or close to 1.4 MHz. In other embodiments, other bandwidths may be used. The control circuit 155 may perform various operations, such as base station-related operations described elsewhere in this disclosure.

[0031] Within the narrow system bandwidth, the transmission circuit 160 can transmit multiple multiplexed downlink physical channels. The multiple downlink physical channels can be multiplexed according to TDM or FDM. The transmission circuit 160 can transmit the multiple multiplexed downlink physical channels in a downlink superframe composed of multiple downlink subframes.

[0032] In a narrow system bandwidth, the receiving circuit 165 can receive multiple multiplexed uplink physical channels. The multiple uplink physical channels can be multiplexed according to TDM or FDM. The receiving circuit 165 can receive the multiple multiplexed uplink physical channels in an uplink superframe composed of multiple uplink subframes.

[0033] As further described below, control circuits 105 and 155 may be involved in measuring channel quality of air interface 190. Channel quality may be based, for example, on physical obstacles between UE 101 and base station 150, electromagnetic signal interference from other sources, reflections, or indirect paths or other such signal noise sources between UE 101 and base station 150. Based on the channel quality, multiple retransmissions of a data block may be scheduled so that transmission circuit 110 may transmit copies of the same data multiple times, and reception circuit 115 may receive multiple copies of the same data multiple times.

[0034] Figure 2 A flowchart of an exemplary method for a UE according to some embodiments is illustrated. In some embodiments, Figure 2 The illustrated method 200 may be performed by Figure 1 The described UE 101 implements.

[0035] In some embodiments, such as Figure 2 As shown, the method 200 for UE includes the following steps: S202, receiving at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition (note that the Tx event can only be configured together with the Ax event) from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition or an A5 event condition, and the Tx event condition is a time-based trigger condition; S204, evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; S206, in response to determining that the Ax event condition or the Tx event condition is satisfied, determining a trigger cell for performing CHO.

[0036] According to the method of some embodiments of the present disclosure, by means of the Ax event condition and the Tx event condition included in at least one CHO command, a time-based CHO trigger event can be implemented in the case of a TN. In addition, since the CHO procedure is initiated when the Ax event condition or the Tx event condition is met, the UE can implement a relaxed CHO condition.

[0037] In the following, each step of the method 200 will be described in detail.

[0038] At step S202, the UE receives at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition or an A5 event condition, and the Tx event condition is a time-based trigger condition.

[0039] At step S204 , the UE evaluates both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied.

[0040] At step S206 , in response to determining that the Ax event condition or the Tx event condition is satisfied, the UE determines a triggering cell for performing CHO.

[0041] In some embodiments, the UE may be a UE that does not support GNSS. For example, the UE may be a NES UE that does not support GNSS or an IAB UE that does not support GNSS.

[0042] In an embodiment where the UE is a NES UE, the method 200 may allow the NES UE to apply relaxed CHO conditions starting from a fixed time when the source cell cannot serve the UE well. The fixed time may be the time when the source cell plans to be turned off (which means that the source cell cannot serve the UE after being turned off). The fixed time may also be the time when the source cell plans to activate cell discontinuous transmission (DTX) or discontinuous reception (DRX) with a longer inactivity duration (which means that the UE's quality of service (QoS) may be degraded in the source cell).

[0043] In an embodiment where the UE is an IAB UE, the method 200 may distribute mobility events of the onboard UE to avoid random access channel (RACH) collisions.

[0044] In some embodiments, whether the UE supports GNSS may be derived via a UE capability report.

[0045] In some embodiments, when there are multiple triggering cells, one of the multiple triggering cells may be selected based on UE specific implementation, so that the selected cell may provide better channel quality.

[0046] In some embodiments, the Tx event condition may include a T1 event condition including a T1 threshold and a first duration using a coordinated universal time (UTC) time. The UTC time may be included in a radio resource control (RRC) message and may be a time in an upcoming system frame number (SFN) boundary of a source cell. Alternatively, the UTC time may be obtained from a system information block type 9 (SIB9). Thus, the UE is able to obtain UTC timing from the BS. The Tx event condition is satisfied when the time measured at the UE becomes greater than the T1 threshold but less than the sum of the T1 threshold and the first duration.

[0047] In some embodiments, the base station may also send the UTC time together with at least one CHO command to the UE not supporting GNSS via an RRC message.

[0048] Figure 3 An exemplary diagram illustrating a T1 event condition according to some embodiments. Figure 3 , t1 is the time of the T1 threshold, and t2 is the time of the first duration after the T1 threshold. When the time for switching measured at the UE is between t1 and t2, the Tx event condition is met.

[0049] In some embodiments, the Tx event condition may include a T2 event condition including a T2 threshold based on the source cell, and wherein the Tx event condition is met when the time measured at the UE becomes greater than the T2 threshold.

[0050] Figure 4A An exemplary diagram illustrating T2 event conditions according to some embodiments. Figure 4A , t1 is the time of T2 threshold. When the time for switching measured at the UE is after t1, the Tx event condition is met.

[0051] In some embodiments, the T2 event condition may also include a second duration configured based on one of a time slot, a subframe, and an absolute time. That is, the second duration may be x time slots, x subframes, or x absolute times (e.g., in milliseconds). The Tx event condition is met when the time measured at the UE becomes greater than the T2 threshold but less than the sum of the T2 threshold and the second duration.

[0052] Figure 4B Another exemplary diagram illustrating a T2 event condition according to some embodiments. Figure 4B , t1 is the time of the T2 threshold, and t2 is the time of the second duration after the T2 threshold. When the time for switching measured at the UE is between t1 and t2, the Tx event condition is met.

[0053] In some embodiments, the T2 threshold may be based on the source cell. The T2 threshold may be configured based on: a system frame number (SFN) index of the source cell, and a time slot index (i.e., SFN index + time slot index); a SFN index and a subframe index (i.e., SFN index + subframe index); a SFN index and an absolute time offset (i.e., SFN index + absolute time offset (e.g., in ms)); a super SFN (H-SFN) index of the source cell, a SFN index, and a time slot index (i.e., H-SFN + SFN + subframe index); a H-SFN index, a SFN index, and a subframe index (i.e., H-SFN + SFN + subframe index); or a H-SFN index, a SFN index, and an absolute time offset (i.e., H-SFN + SFN + absolute time offset (e.g., in ms)).

[0054] In some embodiments, the Tx event condition may include a T3 event condition including a timer having an expiration time that starts at the time of reception of the CHO command by the UE. The expiration time may be configured based on one of a time slot, a subframe, and an absolute time. That is, the expiration time may be x time slots, x subframes, or x absolute times (e.g., in milliseconds). The Tx event condition is satisfied when the time measured at the UE becomes greater than the sum of the reception time and the expiration time.

[0055] Figure 5A An exemplary diagram illustrating T3 event conditions according to some embodiments. Figure 5A , t1 is the time of the T3 threshold, and t2 is the time after the T3 threshold after the expiration time. When the time for switching measured at the UE is after t2, the Tx event condition is met.

[0056] In some embodiments, the T3 event condition may also include a third duration configured based on one of a time slot, a subframe, and an absolute time. That is, the third duration may be x time slots, x subframes, or x absolute times (e.g., in milliseconds). The Tx event condition is met when the time measured at the UE becomes greater than the sum of the reception time of the expiration time but less than the sum of the reception time, the expiration time, and the third duration.

[0057] Figure 5B Another exemplary diagram illustrating a T3 event condition according to some embodiments. Figure 5B , t1 is the time of T3 threshold, t2 is the time of expiration time after T3 threshold, and t3 is the time of third duration after t2. When the time for switching measured at the UE is between t2 and t3, the Tx event condition is met.

[0058] According to some embodiments, by using Tx event conditions, the CHO execution time of the UE may be spread out for HO load distribution considerations.

[0059] In some embodiments, step S206 may include: in response to determining that the Ax event condition is satisfied when the Tx event condition is not satisfied, treating the candidate cell satisfying the Ax event condition as a triggering cell. Figures 3 to 5B Step S206 is described in detail. Figure 3 , if the Ax event condition is met when the time measured at the UE is before t1 or after t2, the UE regards the candidate cell that meets the Ax event condition as a triggering cell. Figure 4A , if the Ax event condition is met when the time measured at the UE is before t1, the UE regards the candidate cell that meets the Ax event condition as a triggering cell. Figure 4B , if the Ax event condition is met when the time measured at the UE is before t1 or after t2, the UE regards the candidate cell that meets the Ax event condition as a triggering cell. Figure 5A , if the Ax event condition is met when the time measured at the UE is before t2, the UE regards the candidate cell that meets the Ax event condition as a triggering cell. Figure 5B , if the Ax event condition is met when the time measured at the UE is before t2 or after t3, the UE regards the candidate cell that meets the Ax event condition as a triggering cell.

[0060] See below for more information Figures 3 to 5B Another case of determining that the Tx event condition is satisfied when the Ax event condition is not satisfied is described in detail. Figure 3 , it may be the case that the Ax event condition has not been met, but the time measured at the UE is between t1 and t2. Figure 4A , it may be the case that the Ax event condition has not yet been met, but the time measured at the UE is after t1. Figure 4B , it may be the case that the Ax event condition has not been met, but the time measured at the UE is between t1 and t2. Figure 5A , it may be the case that the Ax event condition has not yet been met, but the time measured at the UE is after t2. Figure 5B , it may be the case that the Ax event condition has not been met, but the time measured at the UE is between t2 and t3.

[0061] In some embodiments, step S206 may include: in response to determining that the Tx event condition is met when the Ax event condition is not met, determining whether an additional Ax event condition having a network energy saving (NES) dedicated threshold included in the CHO command is met; and in response to determining that the additional Ax event condition is met, treating the candidate cell that meets the additional Ax event condition as a triggering cell. In one example, the Ax event condition is not indicated as "NES", and the additional Ax event condition is indicated as "NES". The additional Ax event condition is configured to be evaluated only when the Tx event condition is met. In one example, the methods of these embodiments allow up to 3 CHO conditions (i.e., Tx event conditions, Ax event conditions, and additional Ax event conditions), and are applicable to situations where the source cell will activate cell DTX / DRX.

[0062] In some embodiments, the additional Ax event condition is the same type as the Ax event condition but has different event thresholds, or the additional Ax event condition is different from the type of the Ax event condition. For example, the Ax event condition can be an A5 event condition, and the additional Ax event condition can also be an A5 event condition. However, the additional Ax event condition can have a looser A5 threshold than the Ax event condition, making it easier to initiate the CHO procedure based on the additional Ax event. For another example, the Ax event condition can be an A5 event condition, and the additional Ax event condition can be a looser A4 event condition. This configuration also makes it easier to initiate the CHO procedure based on the additional Ax event.

[0063] In one example, the above process can be configured as follows:

[0064] 2> If any condEventId within the condExecutionCond associated to condReconfigId is associated with condEventTx:

[0065] 3> If the A3 or A4 or A5 event associated to the measId not indicated as "NES" in the condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0067] 4> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0068] 4> Initiate conditional reconfiguration execution, as specified in 5.3.5.13.5;

[0069] 3> Otherwise if the conditions associated with the target in the stored condRRCReconfig are met

[0070] Tx event of measId in condTriggerConfig of the candidate cell:

[0071] 4> If the A3 or A4 or A5 event associated to the measId indicated as "NES" in the condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0072] 5> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0073] 5> Initiate conditional reconfiguration execution as specified in 5.3.5.13.5.

[0074] In some embodiments, step S206 may include: in response to determining that the Tx event condition is met when the Ax event condition is not met, applying a threshold offset to the Ax event condition; determining whether the Ax event condition with the threshold offset is met; and in response to determining that the Ax event condition with the threshold offset is met, treating the candidate cell that meets the Ax event condition with the threshold offset as a triggering cell. Considering whether the source cell is cell-off or cell DTX / DRX, the threshold can be configured differently. By applying the threshold offset to the threshold of the Ax event condition, a looser new threshold can be achieved. In this way, it is easier to initiate a CHO procedure based on a loose new threshold, and a maximum of 3 CHO conditions are not required. The methods of these embodiments are applicable to situations where the source cell will activate cell DTX / DRX.

[0075] In one example, the above process can be configured as follows:

[0076] 2> If any condEventId within the condExecutionCond associated to condReconfigId is associated with condEventTx:

[0077] 3> If the A3 or A4 or A5 event associated to the measId in condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0078] 4> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0079] 4> Initiate conditional reconfiguration execution, as specified in 5.3.5.13.5;

[0080] 3> Otherwise if the conditions associated with the target in the stored condRRCReconfig are met

[0081] Tx event of measId in condTriggerConfig of the candidate cell:

[0082] 4>UE applies the configured threshold offset to the evaluated A3 or A4 or A5 event associated to measId in condTriggerConfig

[0083] 4> If the A3, A4 or A5 event associated with the measId in condTriggerConfig is met:

[0084] 5> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0085] 5> Initiate conditional reconfiguration execution as specified in 5.3.5.13.5.

[0086] In some embodiments, step S206 may include: in response to determining that the Tx event condition is satisfied when the Ax event condition is not satisfied, determining whether a reference signal received power (RSRP) threshold or a reference signal received quality (RSRQ) threshold included in the CHO command is satisfied; in response to determining that the RSRP threshold or the RSRQ threshold is satisfied (i.e., the RSRP of the target candidate cell is greater than or equal to the RSRP threshold, or the RSRQ of the target candidate cell is greater than or equal to the RSRQ threshold), treating the candidate cell that satisfies the RSRP threshold or the RSRQ threshold as a triggering cell. In this way, even if no candidate target cell satisfies the Ax event condition, a second opportunity to initiate the CHO procedure (i.e., considering RSRP or RSRQ) can be provided.

[0087] In one example, the above process can be configured as follows:

[0088] 3> If the A3 or A4 or A5 event associated to the measId in condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0089] 4> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0090] 4> Initiate conditional reconfiguration execution, as specified in 5.3.5.13.5;

[0091] 3> Otherwise if the Tx event associated to the measId in condTriggerConfig for the target candidate cell in the stored condRRCReconfig is satisfied:

[0092] 4> If the RSRP or RSRQ of the target candidate cell is greater than or equal to the configured threshold Th:

[0093] 5> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0094] 5> Initiate conditional reconfiguration execution as specified in 5.3.5.13.5.

[0095] In some embodiments, the RSRP threshold or RSRQ threshold may include the S criterion indicated in the SIB of the source cell. Whether the candidate cell is a suitable cell is determined by checking whether Srxlev>0 and Squal>0. Alternatively, the RSRP threshold or RSRQ threshold may be a new threshold included in the CHO command. The methods of these embodiments are applicable to the case of mobile IAB, or to the case where the source cell is a cell off and does not require a maximum of 3 CHO conditions.

[0096] In some embodiments, whether the UE is to evaluate additional Ax event conditions, to apply a threshold offset to an Ax event condition, or to determine an RSRP threshold or an RSRQ threshold may be indicated in a Tx event condition, a CHO command, or an RRC message.

[0097] In some embodiments, when there is no Tx event condition, method 200 may include: in response to determining that the Ax event condition is met or receiving L1 / L2 signaling from the source cell for triggering CHO execution, determining a triggering cell for performing CHO. That is, in this case, the UE may only be configured with a maximum of two CHO Ax events. In one example, this operation may be similar to the one described in relation to Figure 4A described, and the difference is Figure 4A The t1 in the above formula can be changed to the time when L1 / L2 signaling is received, instead of the T1 threshold. L1 / L2 signaling is UE group common or cell common downlink control information (DCI) / medium access control-control element (MAC-CE).

[0098] In some embodiments, when there is no Tx event condition, method 200 may include: in response to determining that the Ax event condition is met or receiving an indication in a system information block (SIB) of the source cell for triggering CHO execution, determining a triggering cell for performing CHO. That is, in this case, the UE may also be configured with only a maximum of two CHO Ax events. This operation may also be similar to the one regarding Figure 4A The operation described, but the difference is Figure 4A The t1 in can be changed to the time when the SIB is received, instead of the T1 threshold.

[0099] In some embodiments, when there is no Tx event condition, method 200 may further include the following operations. In response to determining that an indication in L1 / L2 signaling or SIB is received when the Ax event condition is not met (e.g., the Ax event condition has not been met but the time measured at the UE is within Figure 4A After t1 in the CHO command, where t1 is the time when the L1 / L2 signaling or the indication in the SIB is received), the UE may perform one of the following operations: evaluating an additional Ax event condition with a NES-specific threshold included in the CHO command to determine a triggering cell; applying a threshold offset to the Ax event condition to determine a triggering cell; or determining whether an RSRP threshold or an RSRQ threshold included in the CHO command is met to determine a triggering cell. These operations may refer to the description of step S206 above and are therefore omitted. Whether the UE is to evaluate an additional Ax event condition, to apply a threshold offset to the Ax event condition, or to determine whether the RSRP threshold or the RSRQ threshold is indicated in an RRC message for receiving L1 / L2 signaling, or is indicated in an indication in the L1 / L2 signaling, or is indicated in an indication in the SIB for receiving an indication in the SIB.

[0100] In one example, the above process can be configured as follows:

[0101] In case of evaluating additional Ax event conditions:

[0102] 3> If the A3 or A4 or A5 event associated to the measId not indicated as "NES" in the condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0103] 4> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0104] 4> Initiate conditional reconfiguration execution, as specified in 5.3.5.13.5;

[0105] 3> Otherwise if L1 / L2 signaling is received / on detection of a change in the indication in the SIB:

[0106] 4> If the A3 or A4 or A5 event associated to the measId indicated as "NES" in the condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0107] 5> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0108] 5> Initiate conditional reconfiguration execution as specified in 5.3.5.13.5.

[0109] In the case where a threshold offset is applied to the Ax event condition:

[0110] 3> If the A3 or A4 or A5 event associated to the measId in condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0111] 4> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0112] 4> Initiate conditional reconfiguration execution, as specified in 5.3.5.13.5;

[0113] 3> Otherwise if L1 / L2 signaling is received / on detection of a change in the indication in the SIB:

[0114] 4>UE applies the configured threshold offset to the evaluated A3 or A4 or A5 event associated to measId in condTriggerConfig

[0115] 4> If the A3, A4 or A5 event associated with the measId in condTriggerConfig is met:

[0116] 5> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0117] 5> Initiate conditional reconfiguration execution as specified in 5.3.5.13.5.

[0118] In the case of determining the RSRP threshold or the RSRQ threshold:

[0119] 3> If the A3 or A4 or A5 event associated to the measId in condTriggerConfig for the target candidate cell in the stored condRRCReconfig is met:

[0120] 4> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0121] 4> Initiate conditional reconfiguration execution, as specified in 5.3.5.13.5;

[0122] 3> Otherwise if L1 / L2 signaling is received / on detection of a change in the indication in the SIB:

[0123] 4> If the RSRP or RSRQ of the target candidate cell is greater than or equal to the configured threshold Th:

[0124] 5> The target candidate cell associated with the condReconfigId in the stored condRRCReconfig is regarded as the triggering cell;

[0125] 5> Initiate conditional reconfiguration execution as specified in 5.3.5.13.5.

[0126] In some embodiments, an apparatus for a user equipment (UE) may include one or more processors configured to perform operations including the following: receiving at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; and determining a trigger cell for performing CHO in response to determining that the Ax event condition or the Tx event condition is satisfied.

[0127] In some embodiments, a computer-readable medium may have stored thereon a computer program that, when executed by one or more processors, causes the one or more processors to perform operations including: receiving at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; and determining a trigger cell for performing CHO in response to determining that the Ax event condition or the Tx event condition is satisfied.

[0128] Figure 6 A flow chart of an exemplary method for a base station according to some embodiments is illustrated. Figure 6 The illustrated method 600 may be performed by Figure 1 The base station 150 described above is implemented.

[0129] In some embodiments, the method 600 for a BS may include the following steps: S602, configuring at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; and S604, providing a CHO command to a user equipment (UE) for determining whether the Ax event condition or the Tx event condition is met.

[0130] In the following, each step of method 600 will be described. Note that for the sake of clarity, the referenced Figure 2 Those elements, expressions, features, etc. described and the corresponding description (regarding the UE).

[0131] At step S602, the base station configures at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition. The Ax event condition includes an A3 event condition, an A4 event condition or an A5 event condition, and the Tx event condition is a time-based trigger condition.

[0132] At step S604, the base station provides a CHO command to the user equipment (UE) for determining whether the Ax event condition or the Tx event condition is satisfied.

[0133] According to the method of some embodiments of the present disclosure, by providing the UE with the Ax event condition and the Tx event condition included in at least one CHO command, a time-based CHO trigger event can be implemented in the case of a TN. In addition, since the CHO procedure is initiated when the Ax event condition or the Tx event condition is met, the UE can implement a relaxed CHO condition.

[0134] In some embodiments, the Tx event condition in method 600 may include one of the following: a T1 event condition including a T1 threshold and a first duration using a coordinated universal time (UTC) time; a T2 event condition including a T2 threshold based on a source cell; a T2 event condition including a T2 threshold based on a source cell and a second duration configured based on one of a time slot, a subframe, and an absolute time; a T3 event condition including a timer having an expiration time starting at a time when the UE receives a CHO command; a T3 event condition including a timer having an expiration time starting at a time when the UE receives a CHO command, and a third duration configured based on one of a time slot, a subframe, and an absolute time. Details about the T1 event condition-T3 event condition and the first to third durations have been described with reference to method 200, and for clarity, the corresponding description is omitted.

[0135] In some embodiments, method 600 may further include providing a radio resource control (RRC) message including the UTC time to the UE.

[0136] In some embodiments, an apparatus for a BS may include one or more processors configured to perform operations including: configuring at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; and providing the CHO command to a user equipment (UE) for determining whether the Ax event condition or the Tx event condition is satisfied.

[0137] In some embodiments, a computer-readable medium may have a computer program stored thereon, which, when executed by one or more processors, causes the one or more processors to perform operations including the following: configuring at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; and providing the CHO command to a user equipment (UE) for determining whether the Ax event condition or the Tx event condition is satisfied.

[0138] Figure 7 An exemplary block diagram of an apparatus for a UE according to some embodiments is illustrated. Figure 7 The illustrated apparatus 700 may be used to implement Figure 2 Method 200 is shown.

[0139] like Figure 7 As illustrated, the apparatus 700 includes a receiving unit 710 , an evaluating unit 720 , and a determining unit 730 .

[0140] The receiving unit 710 is configured to receive at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition or an A5 event condition, and the Tx event condition is a time-based trigger condition.

[0141] The evaluation unit 720 is configured to evaluate both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied.

[0142] The determining unit 730 is configured to determine a triggering cell for performing CHO in response to determining that the Ax event condition or the Tx event condition is satisfied.

[0143] According to the apparatus of some embodiments of the present disclosure, by means of the Ax event condition and the Tx event condition included in at least one CHO command, a time-based CHO trigger event can be implemented in the case of a TN. In addition, since the CHO procedure is initiated when the Ax event condition or the Tx event condition is met, the UE can implement a relaxed CHO condition.

[0144] Figure 8 An exemplary block diagram of an apparatus for a BS according to some embodiments is illustrated. Figure 8 The illustrated apparatus 800 may be used to implement Figure 6 Method 600 is shown.

[0145] like Figure 8 As illustrated, the apparatus 800 includes a configuration unit 810 and a providing unit 820 .

[0146] The configuration unit 810 is configured to configure at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition.

[0147] The providing unit 820 is configured to provide a CHO command to a user equipment (UE) for determining whether an Ax event condition or a Tx event condition is satisfied.

[0148] According to the apparatus of some embodiments of the present disclosure, by providing the UE with the Ax event condition and the Tx event condition included in at least one CHO command, a time-based CHO trigger event can be implemented in the case of a TN. In addition, since the CHO procedure is initiated when the Ax event condition or the Tx event condition is met, the UE can implement a relaxed CHO condition.

[0149] Fig. 9 Example components of the device 900 according to some embodiments are illustrated. In some embodiments, the device 900 may include at least an application circuit 902, a baseband circuit 904, a radio frequency (RF) circuit (shown as RF circuit 920), a front-end module (FEM) circuit (shown as FEM circuit 930), one or more antennas 932, and a power management circuit (PMC) (shown as PMC 934) coupled together as shown in the figure. The components of the illustrated device 900 may be included in a UE or a RAN node. In some embodiments, the device 900 may include fewer elements (for example, the RAN node may not utilize the application circuit 902, but include a processor / controller to process IP data received from the EPC). In some embodiments, the device 900 may include additional elements, such as, for example, a memory / storage device, a display, a camera, a sensor, or an input / output (I / O) interface. In other embodiments, the components described below may be included in more than one device (for example, the circuit may be separately included in more than one device for a cloud-RAN (C-RAN) specific implementation).

[0150] The application circuit 902 may include one or more application processors. For example, the application circuit 902 may include circuits such as, but not limited to, one or more single-core or multi-core processors. The processor may include any combination of a general-purpose processor and a special-purpose processor (e.g., a graphics processor, an application processor, etc.). The processor may be coupled to or may include a memory / storage device, and may be configured to execute instructions stored in the memory / storage device to enable various applications or operating systems to run on the device 900. In some embodiments, the processor of the application circuit 902 may process IP data packets received from the EPC.

[0151] The baseband circuit 904 may include circuits such as, but not limited to, one or more single-core or multi-core processors. The baseband circuit 904 may include one or more baseband processors or control logic components to process baseband signals received from the receive signal path of the RF circuit 920 and generate baseband signals for the transmit signal path of the RF circuit 920. The baseband circuit 904 may interact with the application circuit 902 to generate and process baseband signals and control the operation of the RF circuit 920. For example, in some embodiments, the baseband circuit 904 may include a third generation (3G) baseband processor (3G baseband processor 906), a fourth generation (4G) baseband processor (4G baseband processor 908), a fifth generation (5G) baseband processor (5G baseband processor 910), or other baseband processors 912 of other existing generations, generations under development, or generations to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuit 904 (e.g., one or more of the baseband processors) may handle various radio control functions that implement communication with one or more radio networks via the RF circuit 920. In other embodiments, some or all of the functions of the exemplary baseband processor may be included in a module stored in the memory 918 and executed via the central processing unit (CPU 914). The radio control functions may include, but are not limited to, signal modulation / demodulation, encoding / decoding, radio frequency shifting, etc. In some embodiments, the modulation / demodulation circuit of the baseband circuit 904 may include a fast Fourier transform (FFT), pre-decoding, or constellation mapping / demapping function. In some embodiments, the encoding / decoding circuit of the baseband circuit 904 may include convolution, tail-biting convolution, turbo, Viterbi, or low-density parity check (LDPC) encoder / decoder functions. The implementation of the modulation / demodulation and encoder / decoder functions is not limited to these examples, and may include other suitable functions in other embodiments.

[0152] In some embodiments, the baseband circuit 904 may include a digital signal processor (DSP), such as one or more audio DSPs 916. The one or more audio DSPs 916 may include elements for compression / decompression and echo cancellation, and may include other suitable processing elements in other embodiments. In some embodiments, the components of the baseband circuit may be appropriately combined in a single chip, a single chipset, or disposed on the same circuit board. In some embodiments, some or all of the components of the baseband circuit 904 and the application circuit 902 may be implemented together, such as on a system on a chip (SOC).

[0153] In some embodiments, the baseband circuit 904 may provide communications compatible with one or more radio technologies. For example, in some embodiments, the baseband circuit 904 may support communications with an Evolved Universal Terrestrial Radio Access Network (EUTRAN) or other wireless metropolitan area network (WMAN), wireless local area network (WLAN), wireless personal area network (WPAN). Embodiments in which the baseband circuit 904 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuits.

[0154] RF circuit 920 may enable communication with a wireless network through a non-solid medium using modulated electromagnetic radiation. In various embodiments, RF circuit 920 may include switches, filters, amplifiers, etc. to facilitate communication with a wireless network. RF circuit 920 may include a receive signal path, which may include circuitry for down-converting an RF signal received from FEM circuit 930 and providing a baseband signal to baseband circuit 904. RF circuit 920 may also include a transmit signal path, which may include circuitry for up-converting a baseband signal provided by baseband circuit 904 and providing an RF output signal for transmission to FEM circuit 930.

[0155] In some embodiments, the receive signal path of the RF circuit 920 may include a mixer circuit 922, an amplifier circuit 924, and a filter circuit 926. In some embodiments, the transmit signal path of the RF circuit 920 may include a filter circuit 926 and a mixer circuit 922. The RF circuit 920 may also include a synthesizer circuit 928 for synthesizing frequencies used by the mixer circuit 922 of the receive signal path and the transmit signal path. In some embodiments, the mixer circuit 922 of the receive signal path may be configured to down-convert the RF signal received from the FEM circuit 930 based on the synthesized frequency provided by the synthesizer circuit 928. The amplifier circuit 924 may be configured to amplify the down-converted signal, and the filter circuit 926 may be a low pass filter (LPF) or a band pass filter (BPF) configured to remove unwanted signals from the down-converted signal to generate an output baseband signal. The output baseband signal may be provided to the baseband circuit 904 for further processing. In some embodiments, although this is not required, the output baseband signal may be a zero frequency baseband signal. In some embodiments, mixer circuit 922 of the receive signal path may include a passive mixer, although the scope of the embodiments is not limited in this respect.

[0156] In some embodiments, mixer circuit 922 of the transmit signal path may be configured to up-convert an input baseband signal based on a synthesized frequency provided by synthesizer circuit 928 to generate an RF output signal for FEM circuit 930. The baseband signal may be provided by baseband circuit 904 and may be filtered by filter circuit 926.

[0157] In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may include two or more mixers and may be arranged for quadrature down-conversion and up-conversion, respectively. In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may include two or more mixers and may be arranged for image suppression (e.g., Hartley image suppression). In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may be arranged for direct down-conversion and direct up-conversion, respectively. In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may be configured for superheterodyne operation.

[0158] In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, the RF circuit 920 may include an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC) circuit, and the baseband circuit 904 may include a digital baseband interface to communicate with the RF circuit 920.

[0159] In some dual-mode embodiments, separate radio IC circuits may be provided to process signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[0160] In some embodiments, synthesizer circuit 928 may be a fractional-N synthesizer or a fractional-N / N+1 synthesizer, but the scope of the embodiments is not limited in this regard, as other types of frequency synthesizers may also be suitable. For example, synthesizer circuit 928 may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase-locked loop with a frequency divider.

[0161] The synthesizer circuit 928 may be configured to synthesize an output frequency based on the frequency input and the divider control input for use by the mixer circuit 922 of the RF circuit 920. In some embodiments, the synthesizer circuit 928 may be a fractional-N / N+1 synthesizer.

[0162] In some embodiments, the frequency input may be provided by a voltage controlled oscillator (VCO), although this is not required. The divider control input may be provided by baseband circuitry 904 or application circuitry 902 (such as an application processor) according to the desired output frequency. In some embodiments, the divider control input (e.g., N) may be determined from a lookup table based on the channel indicated by application circuitry 902.

[0163] The synthesizer circuit 928 of the RF circuit 920 may include a frequency divider, a delay locked loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the frequency divider may be a dual-mode frequency divider (DMD), and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by N or N+1 (e.g., based on carry) to provide a fractional division ratio. In some example embodiments, the DLL may include a cascaded, tunable, delay element, a phase detector, a charge pump, and a D-type flip-flop set. In these embodiments, the delay element may be configured to divide the VCO cycle into Nd equal phase groups, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0164] In some embodiments, the synthesizer circuit 928 can be configured to generate the carrier frequency as the output frequency, while in other embodiments, the output frequency can be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used with the quadrature generator and divider circuits to generate multiple signals with multiple different phases relative to each other at the carrier frequency. In some embodiments, the output frequency can be the LO frequency (f LO ). In some embodiments, RF circuit 920 may include an IQ / polarity converter.

[0165] The FEM circuitry 930 may include a receive signal path that may include circuitry configured to operate on RF signals received from one or more antennas 932, amplify the received signals, and provide an amplified version of the received signals to the RF circuitry 920 for further processing. The FEM circuitry 930 may also include a transmit signal path that may include circuitry configured to amplify transmit signals provided by the RF circuitry 920 for transmission by one or more of the one or more antennas 932. In various embodiments, amplification by the transmit or receive signal path may be accomplished only in the RF circuitry 920, only in the FEM circuitry 930, or in both the RF circuitry 920 and the FEM circuitry 930.

[0166] In some embodiments, the FEM circuit 930 may include a TX / RX switch to switch between transmit mode and receive mode operation. The FEM circuit 930 may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuit 930 may include an LNA to amplify the received RF signal and provide the amplified received RF signal as an output (e.g., to the RF circuit 920). The transmit signal path of the FEM circuit 930 may include a power amplifier (PA) to amplify the input RF signal (e.g., provided by the RF circuit 920), and one or more filters to generate an RF signal for subsequent transmission (e.g., through one or more of the one or more antennas 932).

[0167] In some embodiments, the PMC 934 can manage the power provided to the baseband circuit 904. Specifically, the PMC 934 can control power source selection, voltage scaling, battery charging, or DC-DC conversion. When the device 900 is capable of being powered by a battery, for example, when the device 900 is included in a UE, the PMC 934 can generally be included. The PMC 934 can improve power conversion efficiency while providing a desired specific implementation size and heat dissipation characteristics.

[0168] Fig. 9PMC 934 is shown coupled only to baseband circuitry 904. However, in other embodiments, PMC 934 may additionally or alternatively be coupled to other components (such as, but not limited to, application circuitry 902, RF circuitry 920, or FEM circuitry 930) and perform similar power management operations for these components.

[0169] In some embodiments, the PMC 934 may control or otherwise be part of various power saving mechanisms of the device 900. For example, if the device 900 is in an RRC connected state, in which the device remains connected to a RAN node because it expects to receive traffic soon, the device may enter a state known as discontinuous reception mode (DRX) after a period of inactivity. During this state, the device 900 may be powered off for short time intervals, thereby saving power.

[0170] If there is no data traffic activity for an extended period of time, the device 900 may transition to an RRC Idle state, in which the device is disconnected from the network and does not perform operations such as channel quality feedback, handover, etc. The device 900 enters a very low power state and performs paging, in which the device periodically wakes up again to listen to the network and then powers off again. The device 900 cannot receive data in this state, and in order to receive data, the device transitions back to the RRC Connected state.

[0171] An additional power saving mode can keep a device from using the network for longer than the paging interval (which can range from a few seconds to several hours). During this time, the device is completely unable to connect to the network and can be completely powered down. Any data sent during this time will be significantly delayed, and it is assumed that the delay is acceptable.

[0172] The processor of the application circuit 902 and the processor of the baseband circuit 904 can be used to execute elements of one or more instances of the protocol stack. For example, the processor of the baseband circuit 904 can be used alone or in combination to perform layer 3, layer 2, or layer 1 functions, while the processor of the application circuit 902 can utilize data received from these layers (e.g., packet data) and further perform layer 4 functions (e.g., transport communication protocol (TCP) and user datagram protocol (UDP) layers). As mentioned herein, layer 3 may include a radio resource control (RRC) layer, which will be described in further detail below. As mentioned herein, layer 2 may include a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, which will be described in further detail below. As mentioned herein, layer 1 may include a physical (PHY) layer of a UE / RAN node, which will be described in further detail below.

[0173] Fig.10 An example interface 1000 of a baseband circuit according to some embodiments is illustrated. As discussed above, Fig. 9 The baseband circuit 904 may include a 3G baseband processor 906, a 4G baseband processor 908, a 5G baseband processor 910, other baseband processors 912, a CPU 914, and a memory 918 utilized by the processors. As illustrated, each of these processors may include a corresponding memory interface 1002 to send data to / receive data from the memory 918.

[0174] The baseband circuit 904 may also include one or more interfaces to communicatively couple to other circuits / devices, such as a memory interface 1004 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904), an application circuit interface 1006 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904), and an application circuit interface 1007 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904). Fig. 9 1008 (for example, an interface for sending / receiving data to / from the application circuit 902) and an RF circuit interface 1008 (for example, an interface for sending / receiving data to / from the application circuit 902). Fig. 9 an interface for sending / receiving data to / from a RF circuit 920), a wireless hardware connection interface 1010 (e.g., for sending / receiving data to / from a near field communication (NFC) component, Components (e.g. Low power consumption), components and other communication components to send / receive data) and a power management interface 1012 (for example, an interface for sending / receiving power or control signals to / from the PMC 934).

[0175] Fig.11 1 is a block diagram illustrating a component 1100 capable of reading instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and capable of performing any one or more of the methods discussed herein, according to some example embodiments. Specifically, Fig.11 A diagrammatic representation of hardware resources 1102 is shown including one or more processors 1112 (or processor cores), one or more memory / storage devices 1118, and one or more communication resources 1120, each of which may be communicatively coupled via a bus 1122. For embodiments in which node virtualization (e.g., NFV) is utilized, a hypervisor 1104 may be executed to provide an execution environment for one or more network slices / sub-slices to utilize the hardware resources 1102.

[0176] Processor 1112 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP) (such as a baseband processor), an application specific integrated circuit (ASIC), a radio frequency integrated circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, processor 1114 and processor 1116.

[0177] The memory / storage device 1118 may include main memory, disk storage, or any suitable combination thereof. The memory / storage device 1118 may include, but is not limited to, any type of volatile or non-volatile memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state storage, etc.

[0178] The communication resources 1120 may include interconnect or network interface components or other suitable devices to communicate with one or more peripheral devices 1106 or one or more databases 1108 via the network 1110. For example, the communication resources 1120 may include wired communication components (e.g., for coupling via a universal serial bus (USB)), cellular communication components, NFC components, Components (e.g. Low power consumption), components and other communication components.

[0179] The instructions 1124 may include software, programs, applications, applet, applications, or other executable code for causing at least any of the processors 1112 to perform any one or more of the methods discussed herein. The instructions 1124 may reside in whole or in part within at least one of the processor 1112 (e.g., within a cache memory of the processor), the memory / storage device 1118, or any suitable combination thereof. In addition, any portion of the instructions 1124 may be transmitted to the hardware resources 1102 from any combination of the peripheral device 1106 or the database 1108. Thus, the memory of the processor 1112, the memory / storage device 1118, the peripheral device 1106, and the database 1108 are examples of computer-readable and machine-readable media.

[0180] For one or more embodiments, at least one of the components shown in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes and / or methods as described in the Examples section below. For example, the baseband circuit described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the embodiments described below. For another example, the circuits associated with the UE, base station, network element, etc. described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the embodiments described below in the Examples section.

[0181] Fig.12 The architecture of a system 1200 of a network according to some embodiments is illustrated. The system 1200 includes one or more user equipments (UEs), shown in this example as UE 1202 and UE 1204. UE 1202 and UE 1204 are illustrated as smart phones (e.g., handheld touch screen mobile computing devices capable of connecting to one or more cellular networks), but may also include any mobile or non-mobile computing devices, such as personal data assistants (PDAs), pagers, laptop computers, desktop computers, wireless handheld terminals, or any computing device including a wireless communication interface.

[0182] In some embodiments, any of UE 1202 and UE 1204 may include an Internet of Things (IoT) UE, which may include a network access layer designed for low-power IoT applications that utilize short-term UE connections. The IoT UE may utilize technologies such as machine-to-machine (M2M) or machine-type communication (MTC) to exchange data with an MTC server or device via a public land mobile network (PLMN), proximity-based services (ProSe) or device-to-device (D2D) communication, a sensor network, or an IoT network. The M2M or MTC data exchange may be a machine-initiated data exchange. The IoT network describes interconnected IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure) with short-lived connections. The IoT UE may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate connectivity to the IoT network.

[0183] UE 1202 and UE 1204 may be configured to connect (e.g., be communicatively coupled) to a radio access network (RAN) (shown as RAN 1206). RAN 1206 may be, for example, an Evolved Universal Mobile Telecommunications System (E-UMTS) Terrestrial Radio Access Network (E-UTRAN), a Next Generation RAN (NG RAN), or some other type of RAN. UE 1202 and UE 1204 utilize connection 1208 and connection 1210, respectively, each of which includes a physical communication interface or layer (discussed in further detail below); in this example, connection 1208 and connection 1210 are illustrated as air interfaces to achieve communicatively coupling, and may be consistent with a cellular communication protocol, such as a Global System for Mobile Communications (GSM) protocol, a Code Division Multiple Access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a Cellular PTT protocol (POC), a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a Fifth Generation (5G) protocol, a New Radio (NR) protocol, and the like.

[0184] In this embodiment, UE 1202 and UE 1204 may also directly exchange communication data via the ProSe interface 1212. The ProSe interface 1212 may alternatively be referred to as a sidelink interface comprising one or more logical channels including, but not limited to, a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), a physical sidelink discovery channel (PSDCH), and a physical sidelink broadcast channel (PSBCH).

[0185] UE 1204 is shown configured to access an access point (AP) (shown as AP 1214) via connection 1216. Connection 1216 may include a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, where AP 1214 will include Wireless Fidelity (WFI). ) router. In this example, AP 1214 may be connected to the Internet without being connected to the core network of the wireless system (described in further detail below).

[0186] The RAN 1206 may include one or more access nodes that enable connectivity 1208 and connectivity 1210. These access nodes (ANs) may be referred to as base stations (BSs), Node Bs, evolved Node Bs (eNBs), next generation Node Bs (gNBs), RAN nodes, etc., and may include ground stations (e.g., terrestrial access points) or satellite stations that provide coverage within a geographic area (e.g., a cell). The RAN 1206 may include one or more RAN nodes for providing macro cells, such as the macro RAN node 1218, and one or more RAN nodes for providing femto cells or pico cells (e.g., cells with smaller coverage, smaller user capacity, or higher bandwidth than macro cells), such as low power (LP) RAN nodes (such as the LP RAN node 1220).

[0187] Either the macro RAN node 1218 or the LP RAN node 1220 may terminate the air interface protocol and may be the first point of contact for the UE 1202 and the UE 1204. In some embodiments, either the macro RAN node 1218 or the LP RAN node 1220 may fulfill various logical functions of the RAN 1206, including, but not limited to, functions of a radio network controller (RNC), such as radio bearer management, uplink and downlink dynamic radio resource management, data packet scheduling, and mobility management.

[0188] According to some embodiments, UE 1202 and UE 1204 may be configured to communicate with each other or with either macro RAN node 1218 and LP RAN node 1220 over a multi-carrier communication channel using orthogonal frequency division multiplexing (OFDM) communication signals according to various communication techniques, such as but not limited to orthogonal frequency division multiple access (OFDMA) communication techniques (e.g., for downlink communication) or single carrier frequency division multiple access (SC-FDMA) communication techniques (e.g., for uplink and ProSe or sidelink communication), although the scope of the embodiments is not limited in this respect. OFDM signals may include multiple orthogonal subcarriers.

[0189] In some embodiments, a downlink resource grid may be used for downlink transmissions from either the RAN node 1218 and the LP RAN node 1220 to the UE 1202 and the UE 1204, while uplink transmissions may utilize similar techniques. The grid may be a time-frequency grid, referred to as a resource grid or a time-frequency resource grid, which is a physical resource in the downlink in each time slot. For OFDM systems, such a time-frequency plane representation is common practice, which makes radio resource allocation intuitive. Each column and each row of the resource grid corresponds to an OFDM symbol and an OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to a time slot in a radio frame. The smallest time-frequency unit in the resource grid is represented as a resource element. Each resource grid includes a plurality of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block includes a set of resource elements; in the frequency domain, this may represent the minimum amount of resources that can currently be allocated. Such resource blocks are used to transmit several different physical downlink channels.

[0190] The physical downlink shared channel (PDSCH) may carry user data and higher layer signaling to the UE 1202 and the UE 1204. The physical downlink control channel (PDCCH) may carry information about, among other things, transport formats and resource allocations related to the PDSCH channel. The PDCCH may also inform the UE 1202 and the UE 1204 of transport formats, resource allocations, and H-ARQ (Hybrid Automatic Repeat Request) information related to uplink shared channels. Typically, downlink scheduling (allocation of control and shared channel resource blocks to the UE 1204 within the cell) may be performed at either the macro RAN node 1218 and the LP RAN node 1220 based on channel quality information fed back from either the UE 1202 and the UE 1204. Downlink resource allocation information may be sent on the PDCCH for (e.g., allocated to) each of the UE 1202 and the UE 1204.

[0191] PDCCH can use control channel elements (CCE) to transmit control information. Before being mapped to resource elements, the PDCCH complex-valued symbols can first be organized into four tuples, which can then be arranged using a sub-block interleaver for rate matching. One or more of these CCEs can be used to transmit each PDCCH, where each CCE can correspond to four sets of nine physical resource elements, called resource element groups (REGs). Four quadrature phase shift keying (QPSK) symbols can be mapped to each REG. Depending on the size of the downlink control information (DCI) and channel conditions, one or more CCEs can be used to transmit the PDCCH. There can be four or more different PDCCH formats with different numbers of CCEs (e.g., aggregation levels, L=1, 2, 4, or 8) in LTE.

[0192] Some embodiments may use the concept of resource allocation for control channel information, which is an extension of the concept described above. For example, some embodiments may utilize an enhanced physical downlink control channel (EPDCCH) that uses PDSCH resources for control information transmission. One or more enhanced control channel elements (ECCEs) may be used to transmit EPDCCH. Similar to the above, each ECCE may correspond to four sets of nine physical resource elements, referred to as enhanced resource element groups (EREGs). In some cases, ECCEs may have other numbers of EREGs.

[0193] The RAN 1206 is communicatively coupled to a core network (CN) (shown as CN 1228) via an S1 interface 1222. In an embodiment, the CN 1228 may be an evolved packet core (EPC) network, a next generation packet core (NPC) network, or some other type of CN. In this embodiment, the S1 interface 1222 is divided into two parts: an S1-U interface 1224, which carries traffic data between the macro RAN node 1218 and the LP RAN node 1220 and the serving gateway (S-GW) (shown as S-GW 1232); and an S1-mobility management entity (MME) interface (shown as S1-MME interface 1226), which is a signaling interface between the macro RAN node 1218 and the LP RAN node 1220 and the MME 1230.

[0194] In this embodiment, CN 1228 includes MME 1230, S-GW 1232, Packet Data Network (PDN) Gateway (P-GW) (shown as P-GW 1234) and Home Subscriber Server (HSS) (shown as HSS1236). MME 1230 can be similar in function to the control plane of a conventional Serving General Packet Radio Service (GPRS) Support Node (SGSN). MME 1230 can manage access-related mobility aspects such as gateway selection and tracking area list management. HSS1236 can include a database for network users, which includes subscription-related information for supporting network entities to handle communication sessions. Depending on the number of mobile subscribers, the capacity of the equipment, the organization of the network, etc., CN 1228 can include one or more HSS1236. For example, HSS1236 can provide support for routing / roaming, authentication, authorization, naming / addressing resolution, location dependency, etc.

[0195] The S-GW 1232 may terminate the S1 interface 1222 towards the RAN 1206 and route data packets between the RAN 1206 and the CN 1228. In addition, the S-GW 1232 may be a local mobility anchor for inter-RAN node handovers and may also provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful interception, charging, and enforcement of certain policies.

[0196] The P-GW 1234 may terminate the SGi interface towards the PDN. The P-GW 1234 may route data packets between the CN 1228 (e.g., the EPC network) and an external network (such as a network including an application server 1242 (alternatively referred to as an application function (AF)) via an Internet Protocol (IP) interface (illustrated as an IP communication interface 1238). Generally speaking, the application server 1242 may be an element that provides an application that uses IP bearer resources with a core network (e.g., a UMTS packet service (PS) domain, an LTE PS data service, etc.). In this embodiment, the P-GW 1234 is shown as being communicatively coupled to the application server 1242 via the IP communication interface 1238. The application server 1242 may also be configured to support one or more communication services (e.g., voice over Internet protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UE 1202 and UE 1204 via the CN 1228.

[0197] The P-GW 1234 may also be a node for policy enforcement and charging data collection. The Policy and Charging Enforcement Function (PCRF) (shown as PCRF 1240) is a policy and charging control element of the CN 1228. In a non-roaming scenario, there may be a single PCRF in a domestic public land mobile network (HPLMN) associated with an Internet Protocol Connectivity Access Network (IP-CAN) session of a UE. In a roaming scenario with local traffic breakout, there may be two PCRFs associated with an IP-CAN session of a UE: a domestic PCRF (H-PCRF) within the HPLMN and a visited PCRF (V-PCRF) within a visited public land mobile network (VPLMN). The PCRF 1240 may be communicatively coupled to an application server 1242 via the P-GW 1234. The application server 1242 may signal the PCRF 1240 to indicate a new service flow and select appropriate quality of service (QoS) and charging parameters. The PCRF 1240 may provide the rules to a Policy and Charging Enforcement Function (PCEF) (not shown) with the appropriate Traffic Flow Template (TFT) and QoS Class Identifier (QCI), which initiates the QoS and charging specified by the Application Server 1242.

[0198] Additional Embodiments

[0199] For one or more embodiments, at least one of the components shown in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes and / or methods as described in the Examples section below. For example, the baseband circuit described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the embodiments described below. For another example, the circuits associated with the UE, base station, network element, etc. described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the embodiments described below in the Examples section.

[0200] The following examples relate to additional embodiments.

[0201] Embodiment 1 is a method for a user equipment (UE), the method comprising: receiving at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition from a base station (BS), wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; and determining a trigger cell for performing CHO in response to determining that the Ax event condition or the Tx event condition is satisfied.

[0202] Embodiment 2 is a method according to embodiment 1, wherein the Tx event condition includes a T1 event condition, the T1 event condition includes a T1 threshold and a first duration using a coordinated universal time (UTC) time, and wherein the Tx event condition is satisfied when the time measured at the UE becomes greater than the T1 threshold but less than the sum of the T1 threshold and the first duration, wherein the UTC time is included in a radio resource control (RRC) message or can be obtained from a system information block type 9 (SIB9).

[0203] Embodiment 3 is a method according to embodiment 1, wherein the Tx event condition includes a T2 event condition, the T2 event condition includes a T2 threshold based on a source cell, and wherein the Tx event condition is satisfied when the time measured at the UE becomes greater than the T2 threshold.

[0204] Embodiment 4 is a method according to embodiment 3, wherein the T2 event condition also includes a second duration configured based on one of a time slot, a subframe, and an absolute time, and wherein the Tx event condition is met when the time measured at the UE becomes greater than the T2 threshold but less than the sum of the T2 threshold and the second duration.

[0205] Embodiment 5 is a method according to embodiment 3 or 4, wherein the T2 threshold is configured based on: the system frame number (SFN) index of the source cell, and the time slot index; the SFN index and the subframe index; the SFN index and the absolute time offset; the super SFN (H-SFN) index of the source cell, the SFN index and the time slot index; the H-SFN index, the SFN index and the subframe index; or the H-SFN index, the SFN index and the absolute time offset.

[0206] Embodiment 6 is a method according to embodiment 1, wherein the Tx event condition includes a T3 event condition, the T3 event condition includes a timer having an expiration time that starts at the UE's reception time of the CHO command, wherein the expiration time is configured based on one of a time slot, a subframe, and an absolute time, and wherein the Tx event condition is satisfied when the time measured at the UE becomes greater than the sum of the reception time and the expiration time.

[0207] Embodiment 7 is a method according to embodiment 6, wherein the T3 event condition also includes a third duration configured based on one of a time slot, a subframe, and an absolute time, and wherein the Tx event condition is satisfied when the time measured at the UE becomes greater than the sum of the reception time and the expiration time but less than the sum of the reception time, the expiration time, and the third duration.

[0208] Embodiment 8 is a method according to any one of Embodiments 1 to 7, wherein the determining the triggering cell for performing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied includes: in response to determining that the Ax event condition is satisfied when the Tx event condition is not satisfied, treating the candidate cell that satisfies the Ax event condition as the triggering cell.

[0209] Embodiment 9 is a method according to any one of embodiments 1 to 7, wherein the determining of the triggering cell for performing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied includes: in response to determining that the Tx event condition is satisfied when the Ax event condition is not satisfied, determining whether an additional Ax event condition having a network energy saving (NES) dedicated threshold included in the CHO command is satisfied; and in response to determining that the additional Ax event condition is satisfied, treating the candidate cell that satisfies the additional Ax event condition as the triggering cell.

[0210] Embodiment 10 is a method according to embodiment 9, wherein the additional Ax event condition is of the same type as the Ax event condition but has a different event threshold, or the additional Ax event condition is of a different type than the Ax event condition.

[0211] Embodiment 11 is a method according to any one of embodiments 1 to 7, wherein the determining of the triggering cell for performing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied includes: in response to determining that the Tx event condition is satisfied when the Ax event condition is not satisfied, applying a threshold offset to the Ax event condition; determining whether the Ax event condition with the threshold offset is satisfied; and in response to determining that the Ax event condition with the threshold offset is satisfied, treating a candidate cell that satisfies the Ax event condition with the threshold offset as the triggering cell.

[0212] Embodiment 12 is a method according to any one of Embodiments 1 to 7, wherein the determining of the trigger cell for executing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied includes: in response to determining that the Tx event condition is satisfied when the Ax event condition is not satisfied, determining whether a reference signal received power (RSRP) threshold or a reference signal received quality (RSRQ) threshold included in the CHO command is satisfied; in response to determining that the RSRP threshold or the RSRQ threshold is satisfied, treating a candidate cell that satisfies the RSRP threshold or the RSRQ threshold as the trigger cell.

[0213] Embodiment 13 is a method according to embodiment 12, wherein the RSRP threshold or the RSRQ threshold includes an S criterion indicated in a SIB of the source cell or a new threshold included in the CHO command.

[0214] Embodiment 14 is a method according to any one of embodiments 1 to 13, wherein when there are multiple triggering cells, one of the multiple triggering cells is selected based on UE specific implementation.

[0215] Embodiment 15 is a method according to any one of embodiments 9 to 13, wherein the UE is to evaluate the additional Ax event condition, to apply the threshold offset to the Ax event condition, or to determine whether the RSRP threshold or the RSRQ threshold is indicated in the Tx event condition, the CHO command, or the RRC message.

[0216] Embodiment 16 is a method according to embodiment 1, wherein in the absence of the Tx event condition, the method includes: in response to determining that the Ax event condition is met or receiving L1 / L2 signaling from a source cell for triggering CHO execution, determining the triggering cell for executing the CHO, wherein the L1 / L2 signaling is UE group common downlink control information (DCI) / medium access control-control element (MAC-CE) or cell common DCI / MAC-CE.

[0217] Embodiment 17 is a method according to embodiment 1, wherein, in the absence of the Tx event condition, the method includes: in response to determining that the Ax event condition is met or receiving an indication in the system information block (SIB) of the source cell for triggering the CHO execution, determining the triggering cell for executing the CHO.

[0218] Embodiment 18 is a method according to embodiment 16 or 17, the method further comprising: in response to determining that the L1 / L2 signaling or the indication in the SIB is received when the Ax event condition is not met: evaluating an additional Ax event condition having an NES-specific threshold included in the CHO command to determine the triggering cell; applying a threshold offset to the Ax event condition to determine the triggering cell; or determining whether an RSRP threshold or an RSRQ threshold included in the CHO command is met to determine the triggering cell, wherein the UE is to evaluate the additional Ax event condition, to apply the threshold offset to the Ax event condition, or to determine whether the RSRP threshold or the RSRQ threshold is indicated in an RRC message for receiving the L1 / L2 signaling, or is indicated in the indication in the L1 / L2 signaling, or is indicated in the indication in the SIB for receiving the indication in the SIB.

[0219] Embodiment 19 is a device for a user equipment (UE), the device comprising: one or more processors, the one or more processors being configured to execute the steps of the method according to any one of Embodiments 1 to 18.

[0220] Embodiment 20 is a computer-readable medium having a computer program stored thereon, which, when executed by one or more processors, causes the one or more processors to perform the steps of the method according to any one of embodiments 1 to 18.

[0221] Embodiment 21 is a computer program product, which includes a computer program, which, when executed by one or more processors, causes the one or more processors to perform the steps of the method according to any one of embodiments 1 to 18.

[0222] Embodiment 22 is a device for a user equipment (UE), the device comprising means for performing the steps of the method according to any one of embodiments 1 to 18.

[0223] Embodiment 23 is a method for a base station (BS), the method comprising: configuring at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; and providing the CHO command to a user equipment (UE) for determining whether the Ax event condition or the Tx event condition is satisfied.

[0224] Embodiment 24 is a method according to embodiment 23, wherein the Tx event condition includes one of the following items: a T1 event condition, wherein the T1 event condition includes a T1 threshold and a first duration using Coordinated Universal Time (UTC) time; a T2 event condition, wherein the T2 event condition includes a T2 threshold based on a source cell; a T2 event condition, wherein the T2 event condition includes a T2 threshold based on the source cell and a second duration configured based on one of a time slot, a subframe, and an absolute time; a T3 event condition, wherein the T3 event condition includes a timer having an expiration time that starts at the time when the UE receives the CHO command; a T3 event condition, wherein the T3 event condition includes a timer having an expiration time that starts at the time when the UE receives the CHO command, and a third duration configured based on one of a time slot, a subframe, and an absolute time.

[0225] Embodiment 25 is a method according to embodiment 24, the method further comprising: providing a radio resource control (RRC) message including the UTC time to the UE.

[0226] Embodiment 26 is a device for a base station (BS), the device comprising: one or more processors, wherein the one or more processors are configured to execute the steps of the method according to any one of claims 23 to 25.

[0227] Embodiment 27 is a computer-readable medium having a computer program stored thereon, which, when executed by one or more processors, causes the one or more processors to perform the steps of the method according to any one of Embodiments 23 to 25.

[0228] Embodiment 28 is a computer program product, which includes a computer program, which, when executed by one or more processors, causes the one or more processors to perform the steps of the method according to any one of Embodiments 23 to 25.

[0229] Embodiment 29 is an apparatus for a base station (BS), the apparatus comprising means for performing the steps of the method according to any one of embodiments 23 to 25.

[0230] Unless explicitly stated otherwise, any of the embodiments described above may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise form disclosed. In view of the above teachings, modifications and variations are possible or can be obtained from the practice of various embodiments.

[0231] It should be appreciated that the systems described herein include descriptions of specific embodiments. These embodiments may be combined into a single system, partially incorporated into other systems, separated into multiple systems, or otherwise divided or combined. In addition, it is contemplated that parameters / attributes / aspects, etc. of one embodiment may be used in another embodiment. For clarity, these parameters / attributes / aspects, etc. are described only in one or more embodiments, and it should be appreciated that unless otherwise specifically stated herein, these parameters / attributes / aspects, etc. may be combined with or substituted for parameters / attributes, etc. of another embodiment.

[0232] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. In particular, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0233] Although the foregoing has been described in considerable detail for the sake of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles of the invention. It should be noted that there are many alternative ways to implement both the processes and the apparatus described herein. Therefore, the embodiments of the present invention are to be regarded as illustrative rather than restrictive, and the specification is not limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Claims

1. A method for a user equipment (UE), the method comprising: receiving, from a base station (BS), at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; as well as A triggering cell for performing CHO is determined in response to determining that the Ax event condition or the Tx event condition is satisfied.

2. The method according to claim 1, wherein the Tx event condition comprises a T1 event condition, the T1 event condition comprising a T1 threshold and a first duration using a Coordinated Universal Time (UTC) time, and wherein the Tx event condition is satisfied when a time measured at the UE becomes greater than the T1 threshold but less than a sum of the T1 threshold and the first duration, The UTC time is included in a radio resource control (RRC) message or can be obtained from a system information block type 9 (SIB9).

3. The method of claim 1, wherein the Tx event condition comprises a T2 event condition, the T2 event condition comprising a T2 threshold based on a source cell, and wherein the Tx event condition is satisfied when the time measured at the UE becomes greater than the T2 threshold.

4. The method of claim 3, wherein the T2 event condition further comprises a second duration configured based on one of a time slot, a subframe, and an absolute time, and wherein the Tx event condition is satisfied when the time measured at the UE becomes greater than the T2 threshold but less than the sum of the T2 threshold and the second duration.

5. The method according to claim 3 or 4, wherein the T2 threshold is configured based on: The system frame number (SFN) index and time slot index of the source cell; The SFN index and subframe index; The SFN index and absolute time offset; A super SFN (H-SFN) index of the source cell, the SFN index, and the time slot index; The H-SFN index, the SFN index and the subframe index; or The H-SFN index, the SFN index and the absolute time offset.

6. The method of claim 1 , wherein the Tx event condition comprises a T3 event condition, the T3 event condition comprising a timer having an expiration time that starts at a reception time of the CHO command by the UE, wherein the expiration time is configured based on one of a time slot, a subframe, and an absolute time, and wherein the Tx event condition is satisfied when a time measured at the UE becomes greater than a sum of the reception time and the expiration time.

7. The method of claim 6, wherein the T3 event condition further comprises a third duration configured based on one of a time slot, a subframe, and an absolute time, and wherein the Tx event condition is satisfied when the time measured at the UE becomes greater than the sum of the reception time and the expiration time but less than the sum of the reception time, the expiration time, and the third duration.

8. The method according to any one of claims 1 to 7, wherein the determining the triggering cell for performing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied comprises: In response to determining that the Ax event condition is satisfied when the Tx event condition is not satisfied, the candidate cell satisfying the Ax event condition is regarded as the triggering cell.

9. The method according to any one of claims 1 to 7, wherein the determining the triggering cell for performing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied comprises: in response to determining that the Tx event condition is satisfied when the Ax event condition is not satisfied, determining whether an additional Ax event condition having a network energy saving (NES) specific threshold included in the CHO command is satisfied; as well as In response to determining that the additional Ax event condition is satisfied, the candidate cell satisfying the additional Ax event condition is regarded as the triggering cell.

10. The method of claim 9, wherein the additional Ax event condition is of the same type as the Ax event condition but has a different event threshold, or the additional Ax event condition is of a different type than the Ax event condition.

11. The method according to any one of claims 1 to 7, wherein the determining the triggering cell for performing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied comprises: in response to determining that the Tx event condition is satisfied when the Ax event condition is not satisfied, applying a threshold offset to the Ax event condition; determining whether the Ax event condition with the threshold offset is satisfied; as well as In response to determining that the Ax event condition with the threshold offset is satisfied, the candidate cell satisfying the Ax event condition with the threshold offset is considered as the triggering cell.

12. The method according to any one of claims 1 to 7, wherein the determining the triggering cell for performing the CHO in response to determining that the Ax event condition or the Tx event condition is satisfied comprises: In response to determining that the Tx event condition is satisfied when the Ax event condition is not satisfied, determining whether a reference signal received power (RSRP) threshold or a reference signal received quality (RSRQ) threshold included in the CHO command is satisfied; In response to determining that the RSRP threshold or the RSRQ threshold is met, the candidate cell that meets the RSRP threshold or the RSRQ threshold is considered as the triggering cell.

13. The method of claim 12, wherein the RSRP threshold or the RSRQ threshold comprises an S criterion indicated in a SIB of the source cell or a new threshold included in the CHO command.

14. The method according to any one of claims 1 to 13, wherein when there are multiple triggering cells, one of the multiple triggering cells is selected based on UE specific implementation.

15. The method according to any one of claims 9 to 13, wherein the UE is to evaluate the additional Ax event condition, to apply the threshold offset to the Ax event condition, or to determine whether the RSRP threshold or the RSRQ threshold is indicated in the Tx event condition, the CHO command, or the RRC message.

16. The method of claim 1, wherein in the absence of the Tx event condition, the method comprises: In response to determining that the Ax event condition is met or receiving L1 / L2 signaling for triggering CHO execution from a source cell, determining the triggering cell for executing the CHO, The L1 / L2 signaling is UE group common downlink control information (DCI) / medium access control-control element (MAC-CE) or cell common DCI / MAC-CE.

17. The method of claim 1, wherein in the absence of the Tx event condition, the method comprises: In response to determining that the Ax event condition is met or receiving an indication in a system information block (SIB) of a source cell for triggering the CHO execution, the triggering cell for executing the CHO is determined.

18. The method according to claim 16 or 17, further comprising: In response to determining that the indication in the L1 / L2 signaling or the SIB is received when the Ax event condition is not satisfied: evaluating additional Ax event conditions with NES specific thresholds included in the CHO command to determine the triggering cell; applying a threshold offset to the Ax event condition to determine the triggering cell; or determining whether an RSRP threshold or an RSRQ threshold included in the CHO command is met to determine the triggering cell, Wherein the UE is to evaluate the additional Ax event condition, to apply the threshold offset to the Ax event condition, or to determine whether the RSRP threshold or the RSRQ threshold is indicated in an RRC message for receiving the L1 / L2 signaling, or is indicated in the indication in the L1 / L2 signaling, or is indicated in the indication in the SIB for receiving the indication in the SIB.

19. An apparatus for a user equipment (UE), the apparatus comprising: One or more processors configured to perform operations including: receiving, from a base station (BS), at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; as well as A triggering cell for performing CHO is determined in response to determining that the Ax event condition or the Tx event condition is satisfied.

20. A computer readable medium having stored thereon a computer program, the computer program, when executed by one or more processors, causing the one or more processors to perform operations comprising: receiving, from a base station (BS), at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; evaluating both the Ax event condition and the Tx event condition to determine whether the Ax event condition or the Tx event condition is satisfied; as well as A triggering cell for performing CHO is determined in response to determining that the Ax event condition or the Tx event condition is satisfied.

21. A method for a base station (BS), the method comprising: configuring at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; as well as The CHO command is provided to a user equipment (UE) for determining whether the Ax event condition or the Tx event condition is satisfied.

22. The method of claim 21, wherein the Tx event condition comprises one of the following: A T1 event condition, the T1 event condition comprising a T1 threshold and a first duration using a Coordinated Universal Time (UTC) time; A T2 event condition including a T2 threshold value based on the source cell; A T2 event condition including a T2 threshold based on the source cell and a second duration configured based on one of a time slot, a subframe, and an absolute time; a T3 event condition comprising a timer having an expiry time starting at a time of receipt of the CHO command by the UE; A T3 event condition is included having a timer having an expiration time starting at a reception time of the CHO command by the UE and a third duration configured based on one of a time slot, a subframe, and an absolute time.

23. The method according to claim 22, further comprising: A radio resource control (RRC) message including the UTC time is provided to the UE.

24. An apparatus for a base station (BS), the apparatus comprising: One or more processors configured to perform operations including: configuring at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; as well as The CHO command is provided to a user equipment (UE) for determining whether the Ax event condition or the Tx event condition is satisfied.

25. A computer readable medium having stored thereon a computer program, the computer program, when executed by one or more processors, causing the one or more processors to perform operations comprising: configuring at least one conditional handover (CHO) command including an Ax event condition and a Tx event condition, wherein the Ax event condition includes an A3 event condition, an A4 event condition, or an A5 event condition, and the Tx event condition is a time-based trigger condition; and The CHO command is provided to a user equipment (UE) for determining whether the Ax event condition or the Tx event condition is satisfied.

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