NETWORK HANDLING OF PRIMARY SECONDARY CELL GROUP CELL (PSCELL) CHANGE

Methods, devices, and mechanisms for detecting and reporting successful secondary node and/or primary secondary cell group cell (PScell) changes are provided. In one example, a method of wireless communication performed by a first network unit comprises: transmitting, to a second network unit, an indication of a primary secondary cell group cell (PScell) change associated with a user equipment (UE); transmitting, based on the indication, a SPC configuration; and receiving a SPC report, wherein the SPC report is based on the SPC configuration and SPC information associated with the UE.

INTRODUCTION

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). A wireless multiple-access communications system may include a number of base stations (BSs), each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE). To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the long term evolution (LTE) technology to a next generation new radio (NR) technology, which may be referred to as 5thGeneration (5G). For example, NR is designed to provide a lower latency, a higher bandwidth or a higher throughput, and a higher reliability than LTE. NR is designed to operate over a wide array of spectrum bands, for example, from low-frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz, to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high-bandwidth services. Spectrum sharing can extend the benefit of NR technologies to operating entities that may not have access to a licensed spectrum.

When operating in a wireless communications system, a UE may move between coverage areas of multiple different base stations. The UE may report channel measurements. When the BS detects a degradation in channel quality based on the reported channel measurements and/or other channel information, the BS may initiate a handover of UE to another BS that can provide the UE with a better channel quality. In cases where radio signals of a neighboring base station, which may be referred to as a target base station, will provide an enhanced connection with a UE relative to a currently serving (or source) base station, the UE may be handed over from the source base station to the target base station. Such techniques may be referred to as handover procedures or mobility procedures, and help to provide continuous connectivity to a UE as it moves in a wireless communications system. In some systems, a UE may release an active connection with the source base station and establish a new connection with the target base station in response to a handover communication from the source base station. Enhanced techniques for performing handover may help to enhance the overall efficiency and reliability of a wireless communications system. Accordingly, improvements in mobility support are also desirable for NR.

BRIEF SUMMARY OF SOME EXAMPLES

The present disclosure describes methods, systems, and devices for detecting and reporting successful primary secondary cell group cell (PScell) changes in a wireless communication scenario, according to aspects of the present disclosure. For example, a user equipment (UE) may be in communication with a network via two or more network nodes, including a primary or master node (MN) and at least one secondary node (SN). In some instances, channel conditions observed and reported by the UE may trigger or otherwise cause the network to perform a PScell change to reconfigure the UE with a different PScell and/or SN. The present disclosure describes mechanisms that allow for different types of nodes (e.g., MN, SN) to configure a UE for a PScell change and for successful PScell change (SPC) reporting. In some aspects, a network node may be configured to generate or determine a SPC reporting configuration and communicate the configuration with the UE. In some aspects, the node generating the SPC reporting configuration may be a MN. In another aspect, the node may be a SN. The call flow or protocol for configuring the UE for SPC determination and reporting may be based on the type of node determining the SPC reporting configuration. In another aspect, a UE may be configured to detect a SCG failure during or after the PScell change. The present disclosure provides schemes and mechanisms for the UE to detect, store, and/or report SCG failure-related information to report to the network. Based on the SPC and/or SCG failure reporting from the UE, one or more network nodes may perform network optimizations that may reduce the chance of MCG and/or SCG failures in the future.

According to one aspect of the present disclosure, a method of wireless communication performed by a first network unit comprises: transmitting, to a second network unit, an indication of a primary secondary cell group cell (PScell) change associated with a user equipment (UE); transmitting, based on the indication, a SPC report configuration; and receiving a SPC report, wherein the SPC report is based on the SPC report configuration and SPC information associated with the UE.

According to another aspect of the present disclosure, a method of wireless communication performed by a first master node comprises: receiving, from a second master node, a handover (HO) request; transmitting, to a first secondary node (SN), a primary secondary cell group cell (PScell) change request; receiving, from a user equipment (UE), a first message indicating successful HO information is available and successful PScell change information is available; transmitting, to the UE based on the first message, at least one request for the successful HO information and the successful PScell change information; and receiving, from the UE based on the at least one request, a successful HO report indicating the successful HO information and a SPC report indicating the successful PScell change information.

According to another aspect of the present disclosure, a method of wireless communication performed by a user equipment (UE) comprises: receiving, from a secondary node (SN), an SN modification indication; receiving, from the SN based on the SN modification indication, a successful primary secondary cell group cell (PScell) change report configuration; and transmitting a SPC report, wherein the SPC report is based on the SPC report configuration and PScell change information associated with the UE.

According to another aspect of the present disclosure, a method of wireless communication performed by a user equipment (UE) comprises: receiving, from a network node, a reconfiguration message for a PSCell change; detecting, based on the reconfiguration message, a PSCell change failure ; transmitting, to the network node based on the detecting the failure, a secondary cell group (SCG) failure report indicating SCG failure-related information; and transmitting, to the network node after the transmitting the SCG report, a further SCG failure report indicating additional SCG failure-related information.

According to another aspect of the present disclosure, a first network unit comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the first network unit is configured to: transmit, to a second network unit, an indication of a primary secondary cell group cell (PScell) change associated with a user equipment (UE); transmit, based on the indication, a SPC report configuration; and receive a SPC report, wherein the SPC report is based on the SPC report configuration and successful PScell change information associated with the UE.

According to another aspect of the present disclosure, a first master node comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the first master node is configured to: receive, from a second master node, a handover (HO) request; transmit, to a first secondary node (SN), a primary secondary cell group cell (PScell) change request; receive, from a user equipment (UE), a first message indicating successful HO information is available and successful PScell change information is available; transmit, to the UE based on the first message, at least one request for the successful HO information and the successful PScell change information; and receive, from the UE based on the at least one request, a successful HO report indicating the successful HO information and a SPC report indicating the successful PScell change information.

According to another aspect of the present disclosure, a user equipment (UE) comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the UE is configured to: receive, from a secondary node (SN), an SN modification indication; receive, from the SN based on the SN modification indication, a successful primary secondary cell group cell (PScell) change report configuration; and transmit a SPC report, wherein the SPC report is based on the SPC report configuration and PScell change information associated with the UE.

According to another aspect of the present disclosure, a user equipment (UE) comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the UE is configured to: receive, from a network node, a reconfiguration message for a PSCell change; detect, based on the reconfiguration message, a PSCell change failure; transmit, to the network node based on the detecting the failure, a secondary cell group (SCG) failure report indicating SCG failure-related information; and transmit, to the network node after the transmitting the SCG report, a further SCG failure report indicating additional SCG failure-related information.

According to another aspect of the present disclosure, a non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a first network unit, wherein the instructions comprise code for causing the first network unit to: transmit, to a second network unit, an indication of a primary secondary cell group cell (PScell) change associated with a user equipment (UE); transmit, based on the indication, a SPC report configuration; and receive a SPC report, wherein the SPC report is based on the SPC report configuration and successful PScell change information associated with the UE.

According to another aspect of the present disclosure, a non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a first master node, wherein the instructions comprise code for causing the first master node to: receive, from a second master node, a handover (HO) request; transmit, to a first secondary node (SN), a primary secondary cell group cell (PScell) change request; receive, from a user equipment (UE), a first message indicating successful HO information is available and successful PScell change information is available; transmit, to the UE based on the first message, at least one request for the successful HO information and the successful PScell change information; and receive, from the UE based on the at least one request, a successful HO report indicating the successful HO information and a SPC report indicating the successful PScell change information.

According to another aspect of the present disclosure, a non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a user equipment (UE), wherein the instructions comprise code for causing the UE to: receive, from a secondary node (SN), an SN modification indication; receive, from the SN based on the SN modification indication, a successful primary secondary cell group cell (PScell) change report configuration; and transmit a SPC report, wherein the SPC report is based on the SPC report configuration and PScell change information associated with the UE.

According to another aspect of the present disclosure, a non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a user equipment (UE), wherein the instructions comprise code for causing the UE to: receive, from a network node, a reconfiguration message for a PSCell change; detect, based on the reconfiguration message, a PSCell change failure ; transmit, to the network node based on the code for causing the UE to detect the failure, a secondary cell group (SCG) failure report indicating SCG failure-related information; and transmit, to the network node after the code for causing the UE to transmit the SCG report, a further SCG failure report indicating additional SCG failure-related information.

According to another aspect of the present disclosure, a first network unit comprises: means for transmitting, to a second network unit, an indication of a primary secondary cell group cell (PScell) change associated with a user equipment (UE); means for transmitting, based on the indication, a SPC report configuration; and means for receiving a SPC report, wherein the SPC report is based on the SPC report configuration and successful PScell change information associated with the UE.

According to another aspect of the present disclosure, a first master node comprises: means for receiving, from a second master node, a handover (HO) request; means for transmitting, to a first secondary node (SN), a primary secondary cell group cell (PScell) change request; means for receiving, from a user equipment (UE), a first message indicating successful HO information is available and successful PScell change information is available; means for transmitting, to the UE based on the first message, at least one request for the successful HO information and the successful PScell change information; and means for receiving, from the UE based on the at least one request, a successful HO report indicating the successful HO information and a SPC report indicating the successful PScell change information.

According to another aspect of the present disclosure, a user equipment (UE) comprises: means for receiving, from a secondary node (SN), an SN modification indication; means for receiving, from the SN based on the SN modification indication, a successful primary secondary cell group cell (PScell) change report configuration; and means for transmitting a SPC report, wherein the SPC report is based on the SPC report configuration and PScell change information associated with the UE.

According to another aspect of the present disclosure, a user equipment (UE) comprises: means for receiving, from a network node, a reconfiguration message for a PSCell change; means for detecting, based on the reconfiguration message, a PSCell change failure ; means for transmitting, to the network node based on the means for detecting the failure, a secondary cell group (SCG) failure report indicating SCG failure-related information; and means for transmitting, to the network node after the means for transmitting the SCG report, a further SCG failure report indicating additional SCG failure-related information.

DETAILED DESCRIPTION

A wireless channel between the network (e.g., a BS) and a UE may vary over time. The BS may configure a set of beams for the UE, which at any point of time may use one or two serving beams to receive DL transmissions from or transmit UL transmissions to the BS. The BS and the UE may keep track of the serving beam(s) as well as candidate beams. For example, the UE may perform one or more measurements of one or more reference signals configured for the UE and may include the one or more measurements in a channel state information (CSI) report. If a serving beam fails, the BS may reconfigure the UE to use of the candidate beams. Candidate beams may be regularly updated because the channel quality between the BS and the UE may change over time. It may be desirable for the UE update the serving beam(s) according to the channel state. The UE may report the link quality of the serving beam(s) and the candidate beams in a CSI report to the BS, and the BS may process the CSI report and determine whether the UE's serving beam(s) or candidate beam(s) should be reconfigured. If the quality of a beam falls below a threshold, the BS may reconfigure a beam the UE's serving beam(s) or candidate beam(s). The BS may configure the threshold. Based on the determination, the BS may transmit a command to reconfigure the UE's serving beam(s) and/or candidate beam(s) in response to the CSI report.

The BS may configure the UE to periodically report the CSI report to the BS. The CSI report may include, for example, channel quality information (CQI) and/or reference signal received power (RSRP). CQI is an indicator carrying information on the quality of a communication channel. The BS may use the CQI to assist in downlink (DL) scheduling. The BS may use the RSRP to manage beams in multi-beam operations. The UE may perform different combinations of measurements for inclusion in the CSI report. Accordingly, the UE may transmit a CSI report including the CQI but not the RSRP, a CSI report including the RSRP but not the CQI, and/or a CSI report including both the CQI and the RSRP.

Future cellular networks need to support data-hungry applications with enhanced data rates possibly via cell densification. In addition to providing high data rates, it may be equally important to provide reliable handover mechanisms as this directly impacts on the perceived quality of experience for the end-user. In 5G NR, reliable handover mechanisms that provides high data-rates for moderate-to-high speed users in urban environments remains a challenge. In some instances, network operators may deploy base stations and turn them on and off in a coordinated manner to save energy. As a result, radio channel conditions may change dramatically for the mobile users and so the neighboring cell list changes rapidly.

In some aspects, a UE may be configured for dual connectivity with two or more network nodes and on two or more cells. The UE may receive service from a master node (MN) for a master cell group (MCG), and from a secondary node (SN) for a secondary cell group (SCG). In some aspects, the UE may communicate with network via a primary SCG cell, referred to as a PScell. In some instances, the channel condition reporting from the UE may result in the network determining to change the PScell and/or the SN facilitating the PScell communications. The network nodes may coordinate the PScell change, and may configure the UE to detect and report a successful PScell change (SPC). Because multiple network nodes are communicating with the UE, it may be advantageous to define, configure, or otherwise specify the roles and responsibilities of each node in configuring the UE to report PScell change information, as well as the call flow or signaling protocol for facilitating PScell changes.

The present disclosure describes systems, devices, and methods for PScell changes with SPC reporting. For example, a network node may be configured to generate or determine a SPC reporting configuration and communicate the configuration with the UE. In some aspects, the node generating the SPC reporting configuration may be the master node (MN). In another aspect, the node may be a secondary node (SN). The call flow or protocol for configuring the UE for SPC determination and reporting may be based on the type of node determining the SPC reporting configuration. In another aspect, a UE may be configured to detect a SCG failure during or after the PScell change. The present disclosure provides schemes and mechanisms for the UE to detect, store, and/or report SCG failure-related information to report to the network. Based on the SPC and/or SCG failure reporting from the UE, one or more network nodes may perform network optimizations that may reduce the chance of MCG and/or SCG failures in the future.

Aspects of the present disclosure provide several benefits and advantages. For example, the aspects of the present disclosure provide efficient architectures and protocols for configuring UEs to detect and report PScell conditions and/or successful changes, and to perform network optimizations based on the reports. The aspects of the present disclosure also provide for advantageous SCG failure reporting such that the network may be provided with additional useful SCG failure-related information to perform the network optimizations. Further, the present disclosure describes methods and procedures for correlating SCG failure information and SPC information for performing network optimizations, with or without UE context.

A BS105may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown inFIG.1A, the BSs105dand105emay be regular macro BSs, while the BSs105a-105cmay be macro BSs enabled with one of three dimension (3D), full dimension (FD), or massive MIMO. The BSs105a-105cmay take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. The BS105fmay be a small cell BS which may be a home node or portable access point. A BS105may support one or multiple (e.g., two, three, four, and the like) cells. In the example shown inFIG.1A, the BSs105a,105band105care examples of macro BSs for the coverage areas110a,110band110c,respectively. The BSs105dis an example of a pico BS or a femto BS for the coverage area110d.

In some aspects, a UE115attempting to access the network100may perform an initial cell search by detecting a PSS from a BS105. The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE115may then receive a SSS. The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier.

After receiving the PSS and SSS, the UE115may receive a MIB. The MIB may include system information for initial network access and scheduling information for RMSI and/or OSI. After decoding the MIB, the UE115may receive RMSI and/or OSI. The RMSI and/or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (e.g., PDCCH) monitoring, physical UL control channel (PUCCH), physical UL shared channel (PUSCH), power control, and SRS.

After obtaining the MIB, the RMSI and/or the OSI, the UE115can perform a random access procedure to establish a connection with the BS105. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE115may transmit a random access preamble and the BS105may respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, a UL grant, a temporary cell-radio network temporary identifier (C-RNTI), and/or a backoff indicator. Upon receiving the random access response, the UE115may transmit a connection request to the BS105and the BS105may respond with a connection response. The connection response may indicate a contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response can be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE115may transmit a random access preamble and a connection request in a single transmission and the BS105may respond by transmitting a random access response and a connection response in a single transmission.

After establishing a connection, the UE115and the BS105can enter a normal operation stage, where operational data may be exchanged. For example, the BS105may schedule the UE115for UL and/or DL communications. The BS105may transmit UL and/or DL scheduling grants to the UE115via a PDCCH. The scheduling grants may be transmitted in the form of DL control information (DCI). The BS105may transmit a DL communication signal (e.g., carrying data) to the UE115via a PDSCH according to a DL scheduling grant. The UE115may transmit a UL communication signal to the BS105via a PUSCH and/or PUCCH according to a UL scheduling grant.

In some aspects, the BS105may communicate with a UE115using HARQ techniques to improve communication reliability, for example, to provide a URLLC service. The BS105may schedule a UE115for a PDSCH communication by transmitting a DL grant in a PDCCH. The BS105may transmit a DL data packet to the UE115according to the schedule in the PDSCH. The DL data packet may be transmitted in the form of a transport block (TB). If the UE115receives the DL data packet successfully, the UE115may transmit a HARQ ACK to the BS105. Conversely, if the UE115fails to receive the DL transmission successfully, the UE115may transmit a HARQ NACK to the BS105. Upon receiving a HARQ NACK from the UE115, the BS105may retransmit the DL data packet to the UE115. The retransmission may include the same coded version of DL data as the initial transmission. Alternatively, the retransmission may include a different coded version of the DL data than the initial transmission. The UE115may apply soft-combining to combine the encoded data received from the initial transmission and the retransmission for decoding. The BS105and the UE115may also apply HARQ for UL communications using substantially similar mechanisms as the DL HARQ.

In some aspects, the network100may operate over a system BW or a component carrier (CC) BW. The network100may partition the system BW into multiple BWPs (e.g., portions). A BS105may dynamically assign a UE115to operate over a certain BWP (e.g., a certain portion of the system BW). The assigned BWP may be referred to as the active BWP. The UE115may monitor the active BWP for signaling information from the BS105. The BS105may schedule the UE115for UL or DL communications in the active BWP. In some aspects, a BS105may assign a pair of BWPs within the CC to a UE115for UL and DL communications. For example, the BWP pair may include one BWP for UL communications and one BWP for DL communications.

In some aspects, the network100may operate over a shared channel, which may include shared frequency bands and/or unlicensed frequency bands. For example, the network100may be an NR-U network operating over an unlicensed frequency band. In such an aspect, the BSs105and the UEs115may be operated by multiple network operating entities. To avoid collisions, the BSs105and the UEs115may employ a listen-before-talk (LBT) procedure to monitor for transmission opportunities (TXOPs) in the shared channel. A TXOP may also be referred to as COT. For example, a transmitting node (e.g., a BS105or a UE115) may perform an LBT prior to transmitting in the channel. When the LBT passes, the transmitting node may proceed with the transmission. When the LBT fails, the transmitting node may refrain from transmitting in the channel.

An LBT can be based on energy detection (ED) or signal detection. For an energy detection-based LBT, the LBT results in a pass when signal energy measured from the channel is below a threshold. Conversely, the LBT results in a failure when signal energy measured from the channel exceeds the threshold. For a signal detection-based LBT, the LBT results in a pass when a channel reservation signal (e.g., a predetermined preamble signal) is not detected in the channel. Additionally, an LBT may be in a variety of modes. An LBT mode may be, for example, a category 4 (CAT4) LBT, a category 2 (CAT2) LBT, or a category 1 (CAT1) LBT. A CAT1 LBT is referred to a no LBT mode, where no LBT is to be performed prior to a transmission. A CAT2 LBT refers to an LBT without a random backoff period. For instance, a transmitting node may determine a channel measurement in a time interval and determine whether the channel is available or not based on a comparison of the channel measurement against a ED threshold. A CAT4 LBT refers to an LBT with a random backoff and a variable contention window (CW). For instance, a transmitting node may draw a random number and backoff for a duration based on the drawn random number in a certain time unit.

In some aspects, the network100may support sidelink communication among the UEs115over a shared radio frequency band (e.g., in a shared spectrum or an unlicensed spectrum). In some aspects, the UEs115may communicate with each other over a 2.4 GHz unlicensed band, which may be shared by multiple network operating entities using various radio access technologies (RATs) such as NR-U, WiFi, and/or licensed-assisted access (LAA) as shown inFIG.2.

FIG.1Bshows a diagram illustrating an example disaggregated base station102architecture. The disaggregated base station102architecture may include one or more central units (CUs)150that can communicate directly with a core network104via a backhaul link, or indirectly with the core network104through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC)125via an E2link, or a Non-Real Time (Non-RT) RIC145associated with a Service Management and Orchestration (SMO) Framework135, or both). A CU150may communicate with one or more distributed units (DUs)130via respective midhaul links, such as an F1 interface. The DUs130may communicate with one or more radio units (RUs)140via respective fronthaul links. The RUs140may communicate with respective UEs120via one or more radio frequency (RF) access links. In some implementations, the UE120may be simultaneously served by multiple RUs140.

In some aspects, the CU150may host one or more higher layer control functions. Such control functions can include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU150. The CU150may be configured to handle user plane functionality (i.e., Central Unit—User Plane (CU-UP)), control plane functionality (i.e., Central Unit—Control Plane (CU-CP)), or a combination thereof. In some implementations, the CU150can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the E1interface when implemented in an O-RAN configuration. The CU150can be implemented to communicate with the DU130, as necessary, for network control and signaling.

The SMO Framework135may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework135may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O1interface). For virtualized network elements, the SMO Framework135may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud)190) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2interface). Such virtualized network elements can include, but are not limited to, CUs150, DUs130, RUs140and Near-RT RICs125. In some implementations, the SMO Framework135can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB)111, via an O1interface. Additionally, in some implementations, the SMO Framework135can communicate directly with one or more RUs140via an O1interface. The SMO Framework135also may include a Non-RT RIC145configured to support functionality of the SMO Framework135.

The Non-RT RIC145may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC125. The Non-RT RIC145may be coupled to or communicate with (such as via an A1interface) the Near-RT RIC125. The Near-RT RIC125may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2interface) connecting one or more CUs150, one or more DUs130, or both, as well as an O-eNB, with the Near-RT RIC125.

In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC125, the Non-RT RIC145may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC125and may be received at the SMO Framework135or the Non-RT RIC145from non-network data sources or from network functions. In some examples, the Non-RT RIC145or the Near-RT RIC125may be configured to tune RAN behavior or performance. For example, the Non-RT RIC145may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework135(such as reconfiguration via O1) or via creation of RAN management policies (such as A1policies).

FIG.2illustrates a wireless communication network200that provisions for user equipment reporting according to some aspects of the present disclosure. The network200may correspond to a portion of the network100.FIG.2illustrates two BSs205(shown as205aand205b) and six UEs215(shown as215a1,215a2,215a3,215a4,215b1, and215b2) for purposes of simplicity of discussion, though it will be recognized that embodiments of the present disclosure may scale to any suitable number of UEs215(e.g., the about 2, 3, 4, 5, 7 or more) and/or BSs205(e.g., the about 1, 3 or more). The BS205and the UEs215may be similar to the BSs105and the UEs115, respectively. The BSs205and the UEs215may share the same radio frequency band for communications. In some instances, the radio frequency band may be a 2.4 GHz unlicensed band, a 5 GHz unlicensed band, or a 6 GHz unlicensed band. In general, the shared radio frequency band may be at any suitable frequency.

The BS205aand the UEs215a1-215a4may be operated by a first network operating entity. The BS205band the UEs215b1-215b2may be operated by a second network operating entity. In some aspects, the first network operating entity may utilize a same RAT as the second network operating entity. For instance, the BS205aand the UEs215a1-215a4of the first network operating entity and the BS205band the UEs215b1-215b2of the second network operating entity are NR-U devices. In some other aspects, the first network operating entity may utilize a different RAT than the second network operating entity. For instance, the BS205aand the UEs215a1-215a4of the first network operating entity may utilize NR-U technology while the BS205band the UEs215b1-215b2of the second network operating entity may utilize WiFi or LAA technology.

In the network200, some of the UEs215a1-215a4may communicate with each other in peer-to-peer communications. For example, the UE215a1may communicate with the UE215a2over a sidelink252, the UE215a3may communicate with the UE215a4over another sidelink251, and the UE215b1may communicate with the UE215b2over yet another sidelink254. The sidelinks251,252, and254are unicast bidirectional links. Some of the UEs215may also communicate with the BS205aor the BS205bin a UL direction and/or a DL direction via communication links253. For instance, the UE215a1,215a3, and215a4are within a coverage area210of the BS205a,and thus may be in communication with the BS205a.The UE215a2is outside the coverage area210, and thus may not be in direct communication with the BS205a.In some instances, the UE215a1may operate as a relay for the UE215a2to reach the BS205a.Similarly, the UE215b1is within a coverage area212of the BS205b,and thus may be in communication with the BS205band may operate as a relay for the UE215b2to reach the BS205b.In some aspects, some of the UEs215are associated with vehicles (e.g., similar to the UEs115i-k) and the communications over the sidelinks251,252, and254may be C-V2X communications. C-V2X communications may refer to communications between vehicles and any other wireless communication devices in a cellular network.

FIG.3illustrates an example of a wireless communications system300that supports a handover mechanism and a primary secondary cell group cell (PScell) change in wireless communications according to some aspects of the present disclosure. In some examples, wireless communications system300may implement aspects of wireless communications system100. In some examples, wireless communications system300may implement aspects of wireless communications system100. The wireless communications system300may include a first base station105A, a second base station105B, a third base station105C, a fourth base station105D, and UE115B, which may be examples of a base station105and a UE115, as described with reference toFIG.1A. In some aspects, the BSs105may be referred to as network nodes.

First base station105A may be a source base station105and the second base station105B may be a target base station105in a handover315of the UE115B from the first base station105A to the second base station105B. First base station105A and second base station105B may be in communication with each other, such as via backhaul link134(e.g., via an X2, Xn, or other interface), which may be a wired or wireless interface. While the example ofFIG.3shows the first base station105A in direct communication with the second base station105B, in other cases the communication may be indirect, such as via a core network (e.g., core network130orFIG.1). In this example, the UE115B and the first base station105A may establish a first connection305. In the event that a handover is triggered, the UE115B may establish a second connection310with the second base station105B.

The third base station105B may be a source base station105for a secondary cell and the fourth base station105D may be a target base station105for the secondary cell in a PSCell change330of the UE115B from the third base station105C to the fourth base station105D. Third base station105C and fourth base station105D may be in communication with each other, such as via backhaul link136(e.g., via an X2, Xn, or other interface), which may be a wired or wireless interface. While the example ofFIG.3shows the third base station105C in direct communication with the fourth base station105D, in other cases the communication may be indirect, such as via a core network (e.g., core network130orFIG.1). In this example, the UE115B and the third base station105C may establish a first PScell connection320. In the event that a PScell change is triggered, the UE115B may establish a second connection325with the fourth base station105D. Various techniques as discussed herein provide for efficient handovers and PScell changes including mechanisms for initiating, configuring, and reporting PScell changes.

FIG.4is a signaling diagram illustrating a PScell change procedure400facilitated or otherwise controlled by a master node (MN) according to some aspects of the present disclosure. The PScell change procedure400may include a master node (MN)105A, a source secondary node (S-SN)105C, a target SN (T-SN)105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure400may implement aspects of the wireless communications system100and200. For example, the MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the MN configures the UE115to determine a successful PScell change and/or for PScell change reporting. As illustrated, the PScell change procedure400includes a number of enumerated steps, but embodiments of the PScell change procedure400may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure400, the operations between the MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure400, or other operations may be added to the PScell change procedure400.

At step405, a master node (MN)105A transmits a secondary node (SN) addition request to a target SN (T-SN)105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the MN may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the source secondary node (S-SN)105C. The UE115may transmit, to the MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the MN105A, may determine to perform a PScell change based on the report.

At step410, the T-SN105D transmits, to the MN105A, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information.

At step415, the MN105A transmits, to the S-SN105C, a SN release request requesting that the S-SN105C release or discontinue communications with the UE115. In some aspects, the SN release request may comprise an Xn message.

At step420, the S-SN105C transmits, to the MN105A, a SN release request acknowledgement based on the SN release request. In some aspects, the SN release request acknowledgement may comprise an Xn message.

At step425, the MN105A transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate a successful PScell change (SPC) configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate one or more trigger events and/or conditions to determine whether the PScell change is successful. In some aspects, the SPC configuration may include or indicate one or more timer values or other thresholds that the UE115may use to determine whether the PScell change is successful. For example, the SPC configuration may include at least one of a T304 threshold, a T310 threshold, and/or a T312 threshold. In the illustrated example, the MN105A may configure the SPC configuration autonomously. However, in other examples, (e.g., as illustrated inFIG.5), the SPC configuration may be configured and/or determined by one or more other network nodes, such as the S-SN105C and/or the T-SN105D.

At step430, the UE115determines that one or more trigger conditions have been met for the PScell change based on the SPC configuration transmitted at step425. In some aspects, the conditions may be based on timer values or thresholds indicated in the SPC configuration. For example, the UE115may determine that the PScell change is successful based on one or more of a T304 threshold, a T310 threshold, and/or a T312 threshold.

At step435, the UE115transmits, to the MN105A based on the SPC configuration and the determination of step430, a RRC Reconfiguration Complete message. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step440, the MN105A transmits, to the T-SN105D, a SN Reconfiguration complete message. In some aspects, the SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step445, the MN105A transmits, to the UE115based on the indication that PScell change information is available, an information request. In some aspects, the information request may include a UEInformationRequest message including or indicating a SPC report request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step450, the UE115transmits, to the MN105A, a UE information response or report based on the information request transmitted at step440. In some aspects, the UE information response includes a UEInformationResponse message including or indicating a SPC report. In some aspects, the SPC report may comprise information associated with the PScell change. For example, the SPC report may indicate one or more conditional events or triggers detected by the UE that indicate a successful PScell change. In some aspects, the UEInformationResponse message may comprise a RRC message or IE.

At step455, based on the SPC report, the MN105A performs one or more network optimizations. For example, in some aspects, the MN105A may update one or more timer thresholds associated with radio link monitoring (RLM) and/or beam failure detection (BFD) of a MCG and/or SCG. In another aspect, the MN105A may detect near failure scenarios during a successful PScell change and/or a successful handover (HO).

FIG.5is a signaling diagram illustrating a PScell change procedure500facilitated, initiated, and/or otherwise controlled by a SN according to some aspects of the present disclosure. The PScell change procedure500may include a MN105A, a S-SN105C, a T-SN105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure500may implement aspects of the wireless communications system100and200. For example, the MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the SN initiates a PScell change and is at least partially involved in the configuration of the UE115to determine a successful PScell change and/or for PScell change reporting. As illustrated, the PScell change procedure500includes a number of enumerated steps, but embodiments of the PScell change procedure500may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure500, the operations between the MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure500, or other operations may be added to the PScell change procedure500.

At step505, a S-SN105C transmits, and a MN105A receives, a SN change required message causing the MN105A to proceed with an SN addition, release, or other SN modification. In another aspect, the SN change required message may include or indicate one or more SPC configuration parameters. For example, the SN change required message may comprise a first portion of the SPC configuration. The S-SN105C may determine and indicate in the SN change required message, at least one timer value or threshold. For example, the S-SN105C may determine and indicate in the SN change required message at least one of a T310 timer value or threshold, and/or a T312 timer value or threshold.

At step510, a MN105A transmits, based on the SN change required message received from the S-SN105C, a SN addition request to a T-SN105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the MN may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the S-SN105C. The UE115may transmit, to the MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the MN105A, may determine to perform a PScell change based on the report.

At step515, the T-SN105D transmits, to the MN105A, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information. In some aspects, the SN addition acknowledge message may include one or more SPC configuration parameters. In this regard, the PSC configuration may include a second portion of a SPC configuration. For example, in some aspects, the SN addition request acknowledgement message may include or indicate a T304 time value or threshold.

At step520, the MN105A transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate SPC configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate a combination of SPC configuration parameters determined by the S-SN105C and/or the T-SN105D and indicated by the SN change required message transmitted at step505and/or the SN addition request acknowledgement message transmitted at step515. In another aspect, the MN105A may determine one or more additional SPC configuration parameters to include in the SPC-Config. Accordingly, the MN105A may combine or aggregate the different portions of the SPC configuration from the S-SN105C and/or the T-SN105D as well as any SPC configuration parameters determined by the MN105A for the SPC-Config.

At step525, the UE115determines that one or more trigger conditions have been met for the PScell change based on the SPC configuration transmitted at step520. In some aspects, the conditions may be based on timer values or thresholds indicated in the SPC configuration. For example, the UE115may determine that the PScell change is successful based on one or more of a T304 threshold, a T310 threshold, and/or a T312 threshold.

At step530, the UE115transmits, to the MN105A based on the SPC configuration and the determination of step525, a RRC Reconfiguration Complete message. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step535, the MN transmits, to the S-SN105C, a SN change confirmation. In some aspects, the SN change confirmation comprises an Xn message.

At step540, the MN105A transmits, to the T-SN105D, a SN Reconfiguration complete message. In some aspects, the transmitting SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step545, the MN105A transmits, to the UE115based on the indication that PScell change information is available, an information request. In some aspects, the information request may include a UEInformationRequest message including or indicating a SPC report request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step550, the UE115transmits, to the MN105A, a UE information response or report based on the information request transmitted at step540. In some aspects, the UE information response includes a UEInformationResponse message including or indicating a SPC report. In some aspects, the SPC report may comprise information associated with the PScell change. In some aspects, the UEInformationResponse message may comprise a RRC message or IE.

At step555, the MN105A transmits or forwards the SPC report included in the UE Information Response to the S-SN105C. In some aspects, step555may comprise transmitting a Xn message indicating one or more of the parameters of the SPC report included in the UE information response transmitted at step550.

At step560, based on the SPC report, the MN105A performs one or more network optimizations. For example, in some aspects, the MN105A may update one or more timer thresholds associated with radio link monitoring (RLM) and/or beam failure detection (BFD) of a MCG and/or SCG. In another aspect, the MN105A may detect near failure scenarios during a successful PScell change and/or a successful handover (HO).

FIG.6is a signaling diagram illustrating a PScell change procedure600facilitated or otherwise controlled by a MN according to some aspects of the present disclosure. The PScell change procedure600may include a MN105A, a S-SN105C, a T-SN105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure600may implement aspects of the wireless communications system100and200. For example, the MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the MN configures the UE115to determine a successful PScell change and/or for PScell change reporting. As illustrated, the PScell change procedure600includes a number of enumerated steps, but embodiments of the PScell change procedure600may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure600, the operations between the MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure600, or other operations may be added to the PScell change procedure600.

At step605, a MN105A transmits a SN addition request to a T-SN105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the MN may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the S-SN105C. The UE115may transmit, to the MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the MN105A, may determine to perform a PScell change based on the report.

At step610, the T-SN105D transmits, to the MN105A, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information.

At step615, the MN105A transmits, to the S-SN105C, a SN release request requesting that the S-SN105C release or discontinue communications with the UE115. In some aspects, the SN release request may comprise an Xn message.

At step620, the S-SN105C transmits, to the MN105A, a SN release request acknowledgement based on the SN release request. In some aspects, the SN release request acknowledgement may comprise an Xn message.

At step625, the MN105A transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate a successful PScell change (SPC) configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate one or more trigger events and/or conditions to determine whether the PScell change is successful. In some aspects, the SPC configuration may include or indicate one or more timer values or other thresholds that the UE115may use to determine whether the PScell change is successful. For example, the SPC configuration may include at least one of a T304 threshold, a T310 threshold, and/or a T312 threshold. In the illustrated example, the MN105A may configure the SPC configuration autonomously. However, in other examples, (e.g., as illustrated inFIG.5), the SPC configuration may be configured and/or determined by one or more other network nodes, such as the S-SN105C and/or the T-SN105D.

At step630, the UE115determines that one or more trigger conditions have been met for the PScell change based on the SPC configuration transmitted at step625. In some aspects, the conditions may be based on timer values or thresholds indicated in the SPC configuration. For example, the UE115may determine that the PScell change is successful based on one or more of a T304 threshold, a T310 threshold, and/or a T312 threshold.

At step635, the UE115transmits, to the MN105A based on the SPC configuration and the determination of step630, a RRC Reconfiguration Complete message. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step640, the MN105A transmits, to the T-SN105D, a SN Reconfiguration complete message. In some aspects, the SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step645, the UE115determines or detects a SCG failure at the T-SN. In some aspects, the SCG failure may occur before the PScell change has completed. In some aspects, detecting the SCG failure may comprise determining that one or more signals or messages were not successfully received. In another aspect, determining the SCG failure may comprise determining or detecting a radio link failure, a failure of SCG reconfiguration, a SCG integrity failure, exceeding a maximum uplink transmission timing difference, a random access failure, and/or any other suitable method of detecting a SCG failure.

At step650, based on detecting the SCG failure, the UE115transmits, to the MN105A, SCG failure information. In some aspects, the SCG failure information includes or indicates information associated with the SCG failure, such as the failure type or the condition that resulted in the SCG failure. In some aspects, the failure type may include an expiration of a T310 timer, a random access problem, a sync reconfiguration failure, a SRB3 integrity failure, and/or any other relevant failure type. In some aspects, the network may use the SCG failure information to modify or update subsequent SCG configurations.

At step655, the MN105A transmits, to the UE115based on the SCG failure information transmitted at step650, an information request. In some aspects, the information request may include a UEInformationRequest message including or indicating a SPC report request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step650, the UE115transmits, to the MN105A, a UE information response or report based on the information request transmitted at step640. In some aspects, the UE information response includes a UEInformationResponse message including or indicating a SPC report. In some aspects, the SPC report may comprise information associated with the PScell change. In some aspects, the UEInformationResponse message may comprise a RRC message or IE.

At step655, based on the SPC report, the MN105A performs one or more network optimizations as explained above.

In some aspects, the MN may correlate information from the SPC report and the SCG failure information, and use the correlated information to perform the network optimizations. In some aspects, the MN105A may correlate the SPC report and the SCG failure information based on UE context associated with the SPC report and the SCG failure information. In other instances, the UE context may not be available. For example, the MN105A may periodically delete the UE context such that the SPC report and the SCG failure information may not be correlated by UE context. In some aspects, the MN105A may be configured to correlate the SPC report and the SCG failure information based on one or more other identifiers or indicators in at least one of the SPC report and/or the SCG failure information.

For example, in some aspects, the SCG failure information may include a SPC report indicator indicating that the SPC report has been sent to the network for the handover and/or SN change. In another example, the SCG failure information may include a SPC Report indicator indicating that there is an SPC report associated with the handover. In another example, the SPC report and the SCG failure information may include or indicate a same C-RNTI. In another aspect, the MN105A may correlate the SCG failure information and the SPC report based on their associated timestamps. For example, the MN105A may determine that the SPC report is correlated with SCG failure information that is received within a time threshold of the SPC report. In another aspect, the MN105A may merge the SPC report with the SCG failure information if the SPC report has not been sent by the time the SCG failure information is generated. In another aspect, the MN105A may merge the SCG failure information with the SPC report if the SCG failure information has not been sent by the time the SPC report is generated. In another aspect, if the SCG failure occurs within a certain time window after the generation of the SPC report, the MN105A may discard the SPC report. In another aspect, the UE115may add a tag or reference indicator to the

SPC report and to the SCG failure information. The reference indicator may be used to correlate the SPC report and the SCG failure information.

FIG.7is a signaling diagram illustrating a PScell change procedure700facilitated or otherwise controlled by a MN according to some aspects of the present disclosure. The PScell change procedure700may include a first MN105A, a second MN105B, a S-SN105C, a T-SN105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure700may implement aspects of the wireless communications system100and200. For example, the first MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the MN configures the UE115to determine a successful PScell change and/or for PScell change reporting. As illustrated, the PScell change procedure700includes a number of enumerated steps, but embodiments of the PScell change procedure700may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure700, the operations between the first MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure700, or other operations may be added to the PScell change procedure700.

At step705, a MN105A transmits a SN addition request to a T-SN105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the MN may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the S-SN105C. The UE115may transmit, to the first MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the first MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the first MN105A, may determine to perform a PScell change based on the report.

At step710, the T-SN105D transmits, to the first MN105A, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information.

At step715, the first MN105A transmits, to the S-SN105C, a SN release request requesting that the S-SN105C release or discontinue communications with the UE115. In some aspects, the SN release request may comprise an Xn message.

At step720, the S-SN105C transmits, to the first MN105A, a SN release request acknowledgement based on the SN release request. In some aspects, the SN release request acknowledgement may comprise an Xn message.

At step725, the first MN105A transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate a successful PScell change (SPC) configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate one or more trigger events and/or conditions to determine whether the PScell change is successful. In some aspects, the SPC configuration may include or indicate one or more timer values or other thresholds that the UE115may use to determine whether the PScell change is successful. For example, the SPC configuration may include at least one of a T304 threshold, a T310 threshold, and/or a T312 threshold. In the illustrated example, the first MN105A may configure the SPC configuration autonomously. However, in other examples, (e.g., as illustrated inFIG.5), the SPC configuration may be configured and/or determined by one or more other network nodes, such as the S-SN105C and/or the T-SN105D.

At step730, the UE115determines that one or more trigger conditions have been met for the PScell change based on the SPC configuration transmitted at step725. In some aspects, the conditions may be based on timer values or thresholds indicated in the SPC configuration. For example, the UE115may determine that the PScell change is successful based on one or more of a T304 threshold, a T310 threshold, and/or a T312 threshold.

At step735, the UE115transmits, to the first MN105A based on the SPC configuration and the determination of step730, a RRC Reconfiguration Complete message. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the first MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step740, the first MN105A transmits, to the T-SN105D, a SN Reconfiguration complete message. In some aspects, the SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step745, the UE115determines or detects a SCG failure at the T-SN. In some aspects, the SCG failure may occur before the PScell change has completed. In some aspects, detecting the SCG failure may comprise determining that one or more signals or messages were not successfully received. In another aspect, determining the SCG failure may comprise determining or detecting a radio link failure, a failure of SCG reconfiguration, a SCG integrity failure, exceeding a maximum uplink transmission timing difference, a random access failure, and/or any other suitable method of detecting a SCG failure.

At step750, based on detecting the SCG failure, the UE115transmits, to the first MN105A, SCG failure information. In some aspects, the SCG failure information includes or indicates information associated with the SCG failure, such as the failure type or the condition that resulted in the SCG failure. In some aspects, the failure type may include an expiration of a T310 timer, a random access problem, a sync reconfiguration failure, a SRB3 integrity failure, and/or any other relevant failure type. In some aspects, the network may use the SCG failure information to modify or update subsequent SCG configurations.

At step755, the first MN105A stores at least a portion of the SCG failure information. In some aspects, the at SCG failure information may be indicated in a SCG failure report. In some aspects, the SCG failure information may include one or more trigger events or conditions associated with a SCG failure.

At step760, the UE115and the second MN105B perform a handover (HO) procedure from the first MN105A to the second MN105B. In some aspects, performing the HO may include transmitting a RRC reconfiguration message including a handover command instructing the UE115to handover from the first MN105A to the second MN105B, in which a handover execution phase begins. The handover command may include information associated with the second MN105B, for example, a random access channel (RACH) preamble assignment for accessing the second MN105B. During the handover execution phase, the UE115may execute the handover by performing a random access procedure with the second MN105B.

At step765, the UE115transmits, to the second MN105B, an indication that a SPC report or SPC information is available.

At step770, the second MN105B transmits, to the UE115and based on receiving the indication that the SPC report is available, a UE information request. In some aspects, the information request may include a UEInformationRequest message including or indicating a SPC report request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step775, the UE115transmits, to the second MN105B, a UE information response or report based on the information request transmitted at step770. In some aspects, the UE information response includes a UEInformationResponse message including or indicating a SPC report. In some aspects, the SPC report may comprise information associated with the PScell change. In some aspects, the UEInformationResponse message may comprise a RRC message or IE.

At step780, the second MN105B transmits, to the first MN105A, the SPC report. In some aspects, the SPC report may include or indicate at least a portion of the SPC information included in the UE information response transmitted at step775.

In some aspects, based on the SPC report, the first MN105A performs one or more network optimizations as explained above with respect to the procedures400and/or500, for example.

In some aspects, the first MN105A may correlate information from the SPC report and the SCG failure information, and use the correlated information to perform the network optimizations. In some aspects, the first MN105A may correlate the SPC report and the SCG failure information based on UE context associated with the SPC report and the SCG failure information. In other instances, the UE context may not be available. For example, the first MN105A may periodically delete the UE context such that the SPC report and the SCG failure information may not be correlated by UE context. In some aspects, the first MN105A may be configured to correlate the SPC report and the SCG failure information based on one or more other identifiers or indicators in at least one of the SPC report and/or the SCG failure information.

For example, in some aspects, the SCG failure information may include a SPC report indicator indicating that the SPC report has been sent to the network for the handover and/or SN change. In another example, the SCG failure information may include a SPC Report indicator indicating that there is an SPC report associated with the handover. In another example, the SPC report and the SCG failure information may include or indicate a same C-RNTI. In another aspect, the first MN105A may correlate the SCG failure information and the SPC report based on their associated timestamps. For example, the first MN105A may determine that the SPC report is correlated with SCG failure information that is received within a time threshold of the SPC report. In another aspect, the first MN105A may merge the SPC report with the SCG failure information if the SPC report has not been sent by the time the SCG failure information is generated. In another aspect, the first MN105A may merge the SCG failure information with the SPC report if the SCG failure information has not been sent by the time the SPC report is generated. In another aspect, if the SCG failure occurs within a certain time window after the generation of the SPC report, the first MN105A may discard the SPC report. In another aspect, the UE115may add a tag or reference indicator to the SPC report and to the SCG failure information. The reference indicator may be used to correlate the SPC report and the SCG failure information.

FIG.8is a signaling diagram illustrating a PScell change procedure800facilitated, initiated, and/or otherwise controlled by a SN according to some aspects of the present disclosure. The PScell change procedure800may include a MN105A, a S-SN105C, a T-SN105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure800may implement aspects of the wireless communications system100and200. For example, the MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the SN initiates a PScell change and is at least partially involved in the configuration of the UE115to determine a successful PScell change and/or for PScell change reporting. The procedure800may further include mechanisms for reporting and correlating SCG failure information with SPC information. As illustrated, the PScell change procedure800includes a number of enumerated steps, but embodiments of the PScell change procedure800may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure800, the operations between the MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure800, or other operations may be added to the PScell change procedure800.

At step805, a S-SN105C transmits, and the first MN105A receives, a SN change required message causing the MN105A to proceed with an SN addition, release, or other SN modification. In another aspect, the SN change required message may include or indicate one or more SPC configuration parameters. For example, the SN change required message may comprise a first portion of the SPC configuration. The S-SN105C may determine and indicate in the SN change required message, at least one timer value or threshold. For example, the S-SN105C may determine and indicate in the SN change required message at least one of a T310 timer value or threshold, and/or a T312 timer value or threshold.

At step810, the first MN105A transmits, based on the SN change required message received from the S-SN105C, a SN addition request to a T-SN105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the first MN105A may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the S-SN105C. The UE115may transmit, to the first MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the first MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the first MN105A, may determine to perform a PScell change based on the report.

At step815, the T-SN105D transmits, to the first MN105A, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information. In some aspects, the SN addition acknowledge message may include one or more SPC configuration parameters. In this regard, the PSC configuration may include a second portion of a SPC configuration. For example, in some aspects, the SN addition request acknowledgement message may include or indicate a T304 time value or threshold.

At step820, the first MN105A transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate SPC configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate a combination of SPC configuration parameters determined by the S-SN105C and/or the T-SN105D and indicated by the SN change required message transmitted at step805and/or the SN addition request acknowledgement message transmitted at step815. In another aspect, the first MN105A may determine one or more additional SPC configuration parameters to include in the SPC-Config. Accordingly, the first MN105A may combine or aggregate the different portions of the SPC configuration from the S-SN105C and/or the T-SN105D as well as any SPC configuration parameters determined by the first MN105A for the SPC-Config.

At step825, the UE115determines that one or more trigger conditions have been met for the PScell change based on the SPC configuration transmitted at step825. In some aspects, the conditions may be based on timer values or thresholds indicated in the SPC configuration. For example, the UE115may determine that the PScell change is successful based on one or more of a T304 threshold, a T310 threshold, and/or a T312 threshold.

At step830, the UE115transmits, to the first MN105A based on the SPC configuration and the determination of step825, a RRC Reconfiguration Complete message. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the first MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step835, the first MN105A transmits, to the S-SN105C, a SN change confirmation. In some aspects, the SN change confirmation comprises an Xn message.

At step840, the first MN105A transmits, to the T-SN105D, a SN Reconfiguration complete message. In some aspects, the transmitting SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step845, the UE115determines or detects a SCG failure at the T-SN. In some aspects, the SCG failure may occur before the PScell change has completed. In some aspects, detecting the SCG failure may comprise determining that one or more signals or messages were not successfully received. In another aspect, determining the SCG failure may comprise determining or detecting a radio link failure, a failure of SCG reconfiguration, a SCG integrity failure, exceeding a maximum uplink transmission timing difference, a random access failure, and/or any other suitable method of detecting a SCG failure.

At step850, based on detecting the SCG failure, the UE115transmits, to the first MN105A, SCG failure information. In some aspects, the SCG failure information includes or indicates information associated with the SCG failure, such as the failure type or the condition that resulted in the SCG failure. In some aspects, the failure type may include an expiration of a T310 timer, a random access problem, a sync reconfiguration failure, a SRB3 integrity failure, and/or any other relevant failure type. In some aspects, the network may use the SCG failure information to modify or update subsequent SCG configurations.

At step855, the first MN105A transmits a SCG failure report to the S-SN105C. In some aspects, the SCG failure report transmitted at step855comprises an Xn message indicating the SCG failure information transmitted at step850.

At step860, the first MN105A transmits, to the UE115based on the SCG failure information transmitted at step850, an information request. In some aspects, the information request may include a UEInformationRequest message including or indicating a SPC report request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step865, the UE115transmits, to the first MN105A, a UE information response or report based on the information request transmitted at step860. In some aspects, the UE information response includes a UEInformationResponse message including or indicating a SPC report. In some aspects, the SPC report may comprise information associated with the PScell change. In some aspects, the UEInformationResponse message may comprise a RRC message or IE.

At step870, the first MN105A transmits, to the S-SN105C, a SPC report. In some aspects, the SPC report may include a Xn message indicating the SPC information transmitted at step865.

At step875, based on the SPC report, the MN105A performs one or more network optimizations.

In some aspects, the S-SN105C may correlate information from the SPC report and the SCG failure information, and use the correlated information to perform the network optimizations. In some aspects, the S-SN105C may correlate the SPC report and the SCG failure information based on UE context associated with the SPC report and the SCG failure information. In other instances, the UE context may not be available. For example, the S-SN105C may periodically delete the UE context such that the SPC report and the SCG failure information may not be correlated by UE context. In some aspects, the S-SN105C may be configured to correlate the SPC report and the SCG failure information based on one or more other identifiers or indicators in at least one of the SPC report and/or the SCG failure information.

For example, in some aspects, the SCG failure information may include a SPC report indicator indicating that the SPC report has been sent to the network for the handover and/or SN change. In another example, the SCG failure information may include a SPC Report indicator indicating that there is an SPC report associated with the handover. In another example, the SPC report and the SCG failure information may include or indicate a same C-RNTI. In another aspect, the S-SN105C may correlate the SCG failure information and the SPC report based on their associated timestamps. For example, the S-SN105C may determine that the SPC report is correlated with SCG failure information that is received within a time threshold of the SPC report. In another aspect, the S-SN105C may merge the SPC report with the SCG failure information if the SPC report has not been sent by the time the SCG failure information is generated. In another aspect, the S-SN105C may merge the SCG failure information with the SPC report if the SCG failure information has not been sent by the time the SPC report is generated. In another aspect, if the SCG failure occurs within a certain time window after the generation of the SPC report, the S-SN105C may discard the SPC report. In another aspect, the UE115may add a tag or reference indicator to the SPC report and to the SCG failure information. The reference indicator may be used to correlate the SPC report and the SCG failure information.

FIG.9is a signaling diagram illustrating a PScell change procedure900facilitated, initiated, and/or otherwise controlled by a SN according to some aspects of the present disclosure. The PScell change procedure900may include a MN105A, a S-SN105C, a T-SN105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure900may implement aspects of the wireless communications system100and200. For example, the MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the SN initiates a PScell change and is at least partially involved in the configuration of the UE115to determine a successful PScell change and/or for PScell change reporting. The procedure900may further include mechanisms for reporting and correlating SCG failure information with SPC information. Further, the procedure900may involve initiating, resuming, or otherwise performing a handover (HO) procedure. As illustrated, the PScell change procedure900includes a number of enumerated steps, but embodiments of the PScell change procedure900may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure900, the operations between the MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure900, or other operations may be added to the PScell change procedure900.

At step905, a S-SN105C transmits, and the first MN105A receives, a SN change required message causing the MN105A to proceed with an SN addition, release, or other SN modification. In another aspect, the SN change required message may include or indicate one or more SPC configuration parameters. For example, the SN change required message may comprise a first portion of the SPC configuration. The S-SN105C may determine and indicate in the SN change required message, at least one timer value or threshold. For example, the S-SN105C may determine and indicate in the SN change required message at least one of a T310 timer value or threshold, and/or a T312 timer value or threshold.

At step910, the first MN105A transmits, based on the SN change required message received from the S-SN105C, a SN addition request to a T-SN105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the first MN105A may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the S-SN105C. The UE115may transmit, to the first MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the first MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the first MN105A, may determine to perform a PScell change based on the report.

At step915, the T-SN105D transmits, to the first MN105A, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information. In some aspects, the SN addition acknowledge message may include one or more SPC configuration parameters. In this regard, the PSC configuration may include a second portion of a SPC configuration. For example, in some aspects, the SN addition request acknowledgement message may include or indicate a T304 time value or threshold.

At step920, the first MN105A transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate SPC configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate a combination of SPC configuration parameters determined by the S-SN105C and/or the T-SN105D and indicated by the SN change required message transmitted at step905and/or the SN addition request acknowledgement message transmitted at step915. In another aspect, the first MN105A may determine one or more additional SPC configuration parameters to include in the SPC-Config. Accordingly, the first MN105A may combine or aggregate the different portions of the SPC configuration from the S-SN105C and/or the T-SN105D as well as any SPC configuration parameters determined by the first MN105A for the SPC-Config.

At step925, the UE115determines that one or more trigger conditions have been met for the PScell change based on the SPC configuration transmitted at step925. In some aspects, the conditions may be based on timer values or thresholds indicated in the SPC configuration. For example, the UE115may determine that the PScell change is successful based on one or more of a T304 threshold, a T310 threshold, and/or a T312 threshold.

At step930, the UE115transmits, to the first MN105A based on the SPC configuration and the determination of step925, a RRC Reconfiguration Complete message. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the first MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step935, the first MN105A transmits, to the S-SN105C, a SN change confirmation. In some aspects, the SN change confirmation comprises an Xn message.

At step940, the first MN105A transmits, to the T-SN105D, a SN Reconfiguration complete message. In some aspects, the transmitting SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step945, the UE115determines or detects a SCG failure at the T-SN. In some aspects, the SCG failure may occur before the PScell change has completed. In some aspects, detecting the SCG failure may comprise determining that one or more signals or messages were not successfully received. In another aspect, determining the SCG failure may comprise determining or detecting a radio link failure, a failure of SCG reconfiguration, a SCG integrity failure, exceeding a maximum uplink transmission timing difference, a random access failure, and/or any other suitable method of detecting a SCG failure.

At step950, based on detecting the SCG failure, the UE115transmits, to the first MN105A, SCG failure information. In some aspects, the SCG failure information includes or indicates information associated with the SCG failure, such as the failure type or the condition that resulted in the SCG failure. In some aspects, the failure type may include an expiration of a T310 timer, a random access problem, a sync reconfiguration failure, a SRB3 integrity failure, and/or any other relevant failure type. In some aspects, the network may use the SCG failure information to modify or update subsequent SCG configurations.

At step955, the first MN105A transmits a SCG failure report to the S-SN105C. In some aspects, the SCG failure report transmitted at step955comprises an Xn message indicating the SCG failure information transmitted at step950.

At step960, the UE115and the second MN105B perform a handover (HO) procedure from the first MN105A to the second MN105B. In some aspects, performing the HO may include obtaining a measurement report from the UE115, transmitting a HO request message to the second MN105B, receiving a HO request acknowledge message from the second MN105B, transmitting a RRC reconfiguration message to the UE115, performing a random access procedure, and/or receiving a RRCReconfigurationComplete message from the UE115.

At step965, the UE115transmits, to the second MN105B, an indication that a SPC report or SPC information is available.

At step970, the second MN105B transmits, to the UE115and based on receiving the indication that the SPC report is available, a UE information request. In some aspects, the information request may include a UEInformationRequest message including or indicating a SPC report request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step975, the UE115transmits, to the second MN105B, a UE information response or report based on the information request transmitted at step970. In some aspects, the UE information response includes a UEInformationResponse message including or indicating a SPC report. In some aspects, the SPC report may comprise information associated with the PScell change. In some aspects, the UEInformationResponse message may comprise a RRC message or IE.

At step980, the second MN105B transmits, to the S-SN105C, the SPC report. In some aspects, the SPC report may include or indicate at least a portion of the SPC information included in the UE information response transmitted at step975.

In some aspects, the S-SN105C may correlate information from the SPC report and the SCG failure information, and use the correlated information to perform the network optimizations. In some aspects, the S-SN105C may correlate the SPC report and the SCG failure information based on UE context associated with the SPC report and the SCG failure information. In other instances, the UE context may not be available. For example, the S-SN105C may periodically delete the UE context such that the SPC report and the SCG failure information may not be correlated by UE context. In some aspects, the S-SN105C may be configured to correlate the SPC report and the SCG failure information based on one or more other identifiers or indicators in at least one of the SPC report and/or the SCG failure information.

For example, in some aspects, the SCG failure information may include a SPC report indicator indicating that the SPC report has been sent to the network for the handover and/or SN change. In another example, the SCG failure information may include a SPC Report indicator indicating that there is an SPC report associated with the handover. In another example, the SPC report and the SCG failure information may include or indicate a same C-RNTI. In another aspect, the S-SN105C may correlate the SCG failure information and the SPC report based on their associated timestamps. For example, the S-SN105C may determine that the SPC report is correlated with SCG failure information that is received within a time threshold of the SPC report. In another aspect, the S-SN105C may merge the SPC report with the SCG failure information if the SPC report has not been sent by the time the SCG failure information is generated. In another aspect, the S-SN105C may merge the SCG failure information with the SPC report if the SCG failure information has not been sent by the time the SPC report is generated. In another aspect, if the SCG failure occurs within a certain time window after the generation of the SPC report, the S-SN105C may discard the SPC report. In another aspect, the UE115may add a tag or reference indicator to the SPC report and to the SCG failure information. The reference indicator may be used to correlate the SPC report and the SCG failure information.

FIG.10is a signaling diagram illustrating a PScell change procedure1000facilitated or otherwise controlled by a SN with limited or no involvement by the MN, according to some aspects of the present disclosure. The PScell change procedure1000may include a MN105A, a SN105C, and a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure1000may implement aspects of the wireless communications system100and200. For example, the MN105A, the SN105C, and the UE115may support a PScell change procedure in which the SN105C configures the UE115to determine a successful PScell change and/or for PScell change reporting. As illustrated, the PScell change procedure1000includes a number of enumerated steps, but embodiments of the PScell change procedure1000may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure1000, the operations between the MN105A, SN105C, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure1000, or other operations may be added to the PScell change procedure1000.

At step1005, the SN105C transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate a successful PScell change (SPC) configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate one or more trigger events and/or conditions to determine whether the PScell change is successful. In some aspects, the SPC configuration may include or indicate one or more timer values or other thresholds that the UE115may use to determine whether the PScell change is successful. For example, the SPC configuration may include at least one of a T304 threshold, a T310 threshold, and/or a T312 threshold. In the illustrated example, the SN105C may configure the SPC configuration autonomously.

At step1010, the UE115transmits, to the SN105C based on the SPC configuration, a RRC Reconfiguration Complete message. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the SN105C indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step1015, the SN105C and the UE115perform a random access procedure to change a PScell or configuration within the SN. In some aspects, the random access procedure comprises the addition, modification, or release of one SCG Scell and/or the release, modification, or addition of another SCG Scell.

In the procedure1000, there may be at least two options for reporting SPC information to the SN105C. A first option is shown as step1020. The dashed lines indicate an optional or alternative step, with step1025also being optional or alternative to step1020. In step1020, the UE115transmits, to the MN105A, an SPC report, and the MN105A forwards the SPC report to the SN105C. In some aspects, step1020comprises transmitting a UL signal from the UE115to the MN105A, and the MN105A transmitting a Xn message to the SN105C indicating the SPC report. For example, step1020may comprise the MN105A and/or the SN105C transmitting a UE information request for an SPC report to the UE115, and the UE115transmitting a UE information response based on the request to the MN105A, where the UE information response includes the SPC report. The MN105A may then transmit or forward the SPC information in the SPC report to the SN105C in an Xn message. In some aspects, the UE115may transmit the SPC report to the MN105A via SRB1.

In step1025, which may be optional or alternative as described above, the UE115transmits the SPC report directly to the SN105C. In some aspects, step1025may comprise the UE115transmitting the SPC report via a UL RRC message. In some aspects, the UE115may transmit the SPC report via SRB3 if SRB3 is available.

FIG.11is a signaling diagram illustrating a PScell change procedure1100facilitated or otherwise controlled by a MN according to some aspects of the present disclosure. The PScell change procedure1100may include a MN105A, a S-SN105C, a T-SN105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure1100may implement aspects of the wireless communications system100and200. For example, the MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the MN configures the UE115to determine a successful PScell change and/or for PScell change reporting. As illustrated, the PScell change procedure1100includes a number of enumerated steps, but embodiments of the PScell change procedure1100may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure1100, the operations between the MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure1100, or other operations may be added to the PScell change procedure1100.

At step1105, the first MN105A transmits, to the second MN105B, a handover (HO) request. In some aspects, the HO request may include a Xn message.

At step1110, the second MN105B transmits a SN addition request to the T-SN105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the first MN105A may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the S-SN105C. The UE115may transmit, to the first MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the first MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the first MN105A, may determine to perform a PScell change based on the report.

At step1115, the T-SN105D transmits, to the second MN105B, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information.

At step1120, the second MN105B transmits, to the first MN105A, a HO request acknowledgement. In some aspects, the HO request acknowledgement may include a Xn message.

At step1125, the first MN105A transmits, to the S-SN105C, a SN release request requesting that the S-SN105C release or discontinue communications with the UE115. In some aspects, the SN release request may comprise an Xn message.

At step1130, the S-SN105C transmits, to the first MN105A, a SN release request acknowledgement based on the SN release request. In some aspects, the SN release request acknowledgement may comprise an Xn message.

At step1135, the first MN105A transmits, to the UE115, a RRCReconfiguration message. The RRCReconfiguration message may comprise or indicate a successful PScell change (SPC) configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate one or more trigger events and/or conditions to determine whether the PScell change is successful. In some aspects, the SPC configuration may include or indicate one or more timer values or other thresholds that the UE115may use to determine whether the PScell change is successful. For example, the SPC configuration may include at least one of a T304 threshold, a T310 threshold, and/or a T312 threshold. In the illustrated example, the MN105A may configure the SPC configuration autonomously. However, in other examples, (e.g., as illustrated inFIG.5), the SPC configuration may be configured and/or determined by one or more other network nodes, such as the S-SN105C and/or the T-SN105D.

At step1140, the UE115determines that one or more trigger conditions have been met for the successful PScell change based on the SPC configuration transmitted at step1135, and that one or more trigger conditions have been met for the HO procedure initiated with the HO request transmitted at step1105. In some aspects, the conditions may be based on timer values or thresholds indicated in the SPC configuration and/or in the HO request. For example, the UE115may determine that the PScell change is successful based on one or more of a T304 threshold, a T310 threshold, and/or a T312 threshold.

At step1145, the UE115transmits, to the second MN105B based on the determination of step1140, a RRC Reconfiguration Complete message. In this regard, the RRC Reconfiguration Complete message is transmitted to the second MN105B and may not be transmitted to the first MN105A which initiated the SN release of the S-SN105C. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE). Further, the RRC Reconfiguration Complete message may include or indicate that successful HO information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successHO-InfoAvailable field or flag indicating to the network that the successful HO information is available.

At step1150, the second MN105B transmits, to the T-SN105D based on the RRC Reconfiguration Complete message, a SN Reconfiguration complete message. In some aspects, the SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step1155, the second MN105B transmits, to the UE115based on the indication that PScell change information is available and the indication that the HO information is available, an information request. In some aspects, the information request may include a UEInformationRequest message including or indicating a SPC report request and a successful HO report request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step1160, the UE115transmits, to the second MN105B, a UE information response or report based on the information request transmitted at step1140. In some aspects, the UE information response includes a UEInformationResponse message including or indicating a SPC report and a successful HO report. In some aspects, the SPC report may comprise information associated with the PScell change. The successful HO report may comprise information associated with the HO. In some aspects, the UEInformationResponse message may comprise a RRC message or IE. In some aspects, based on the SPC report and/or the successful HO report, the second MN105B performs one or more network optimizations.

FIG.12is a signaling diagram illustrating a PScell change procedure1200facilitated, initiated, and/or otherwise controlled by a SN according to some aspects of the present disclosure. The PScell change procedure1200may include a MN105A, a S-SN105C, a T-SN105D, a UE115, which may be examples of the corresponding devices described with reference toFIGS.1A-2. In some examples, the PScell change procedure1200may implement aspects of the wireless communications system100and200. For example, the MN105A, the S-SN105C, the T-SN105D, and the UE115, may support a PScell change procedure in which the SN initiates a PScell change and is at least partially involved in the configuration of the UE115to determine a successful PScell change and/or for PScell change reporting. The procedure1200may further include mechanisms for reporting SCG failure information and additional SCG failure information. As illustrated, the PScell change procedure1200includes a number of enumerated steps, but embodiments of the PScell change procedure1200may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. In the following description of the PScell change procedure1200, the operations between the MN105A, S-SN105C, the T-SN105D, and/or the UE115may be transmitted in a different order or at different times than the exemplary order shown. Certain operations may also be left out of the PScell change procedure1200, or other operations may be added to the PScell change procedure1200.

At step1205, a S-SN105C transmits, and the first MN105A receives, a SN change required message causing the MN105A to proceed with an SN addition, release, or other SN modification. In another aspect, the SN change required message may include or indicate one or more SPC configuration parameters. For example, the SN change required message may comprise a first portion of the SPC configuration. The S-SN105C may determine and indicate in the SN change required message, at least one timer value or threshold. For example, the S-SN105C may determine and indicate in the SN change required message at least one of a T310 timer value or threshold, and/or a T312 timer value or threshold.

At step1210, the first MN105A transmits, based on the SN change required message received from the S-SN105C, a SN addition request to a T-SN105D. In some aspects, transmitting the SN addition request may comprise transmitting an Xn message or signal indicating the SN addition request. In some aspects, the SN addition request message may provide or indicate RRC and/or data radio bearer (DRB) configuration information for changing the SN. In some aspects, the first MN105A may transmit the SN addition request based on one or more reports and/or measurements obtained by the UE115. In this regard, the UE115may obtain one or more channel measurements of a primary secondary cell group cell (PScell) facilitated by the S-SN105C. The UE115may transmit, to the first MN105A, S-SN105C, and/or any other network node or device, a report indicating the channel measurements. For example, the UE115may transmit, to the first MN105A and/or to the S-SN105C, a channel state information (CSI) report based on the channel measurements. A network node, such as the first MN105A, may determine to perform a PScell change based on the report.

At step1215, the T-SN105D transmits, to the first MN105A, a SN addition acknowledgement. In some aspects, the SN addition acknowledgement may comprise an Xn message. In some aspects, the SN addition acknowledgement may include information for allocating resources, providing SCG resource configuration, and/or for providing any other suitable information. In some aspects, the SN addition acknowledge message may include one or more SPC configuration parameters. In this regard, the PSC configuration may include a second portion of a SPC configuration. For example, in some aspects, the SN addition request acknowledgement message may include or indicate a T304 time value or threshold.

At step1220, the first MN105A transmits, to the UE115, a RRC Reconfiguration message. The RRC Reconfiguration message may comprise or indicate SPC configuration. In some aspects, the SPC configuration may comprise a SPC-Config. In some aspects, the SPC-Config may include or indicate information for the PScell change. For example, the SPC configuration may indicate a combination of SPC configuration parameters determined by the S-SN105C and/or the T-SN105D and indicated by the SN change required message transmitted at step1205and/or the SN addition request acknowledgement message transmitted at step1215. In another aspect, the first MN105A may determine one or more additional SPC configuration parameters to include in the SPC-Config. Accordingly, the first MN105A may combine or aggregate the different portions of the SPC configuration from the S-SN105C and/or the T-SN105D as well as any SPC configuration parameters determined by the first MN105A for the SPC-Config.

At step1225, the UE115transmits, to the first MN105A, a RRC Reconfiguration Complete message. In some instances, the transmitting the RRC Reconfiguration Complete message may be based on a determination that one or more trigger conditions for a successful PScell change have been met. The RRC Reconfiguration Complete message may include or indicate that successful PScell change information is available. For example, the RRC Reconfiguration Complete message may include or indicate a successPSCellChange-InfoAvailable field or flag indicating to the network that that the successful PScell change information is available. In some aspects, the successful PScell change information may include transmitting a UCI to the first MN105A indicating that the successful PScell change information is available. In other aspects, the successful PScell change information may be carried and/or indicated in a RRC message and/or a media access control-control element (MAC-CE).

At step1230, the first MN105A transmits, to the S-SN105C, a SN change confirmation. In some aspects, the SN change confirmation comprises an Xn message.

At step1235, the first MN105A transmits, to the T-SN105D, a SN Reconfiguration complete message. In some aspects, the transmitting SN Reconfiguration complete message includes transmitting an Xn message including or indicating the SN Reconfiguration complete message.

At step1240, the UE115determines or detects a SCG failure at the T-SN105D. In some aspects, the SCG failure may occur before the PScell change has completed. In some aspects, detecting the SCG failure may comprise determining that one or more signals or messages related to the PScell change were not successfully received. In another aspect, determining the SCG failure may comprise determining or detecting a radio link failure, a failure of SCG reconfiguration, a SCG integrity failure, exceeding a maximum uplink transmission timing difference, a random access failure, and/or any other suitable method of detecting a SCG failure.

At step1245, based on detecting the SCG failure, the UE115transmits, to the first MN105A, SCG failure information. In some aspects, the SCG failure information includes or indicates information associated with the SCG failure, such as the failure type or the condition that resulted in the SCG failure. In some aspects, the failure type may include an expiration of a T310 timer, a random access problem, a sync reconfiguration failure, a SRB3 integrity failure, and/or any other relevant failure type. In some aspects, the network may use the SCG failure information to modify or update subsequent SCG configurations. In some aspects, the SCG failure information may include an indicator that additional SCG failure information is available, as further discussed below.

At step1250, the first MN105A transmits a SCG failure report to the S-SN105C. In some aspects, the SCG failure report transmitted at step1255comprises an Xn message indicating the SCG failure information transmitted at step1250.

At step1255, the UE115stores additional SCG failure information. In some aspects, the UE115may store the additional SCG failure information in a VarSCGFailure-Report variable. In some aspects, as further explained below, the additional SCG failure information may be used to generate an additional SCG failure report. The additional SCG failure report may be similar to the SCG failure report transmitted at step1250, in some aspects. The additional SCG failure information may include, for example, a first satisfied event of CPAC execution. In this regard, there may be multiple event triggers for conditional reconfiguration. In some aspects, a first conditional event may include a conditional reconfiguration candidate (e.g., target cell of a SCG) having better channel conditions (e.g., RSRP, RSRQ, SNR, etc.) than the serving Pcell and/or PScell by a configured offset. In this regard, the trigger event or condition may be met if the candidate RSRP, RSRQ, and/or SNR exceeds the current serving Pcell or PScell by the configured offset. In another aspect, a second conditional event may include the conditional reconfiguration candidate cell having better channel conditions (e.g., RSRP, RSRQ, SNR, etc.) than an absolute threshold. In another aspect, a third conditional event for conditional reconfiguration may include the current serving Pcell and/or PScell having channel conditions that fall below a first absolute threshold and the candidate cell having channel conditions that exceed a second absolute threshold. In some instances, multiple conditional events may occur to trigger the conditional reconfiguration. It may be beneficial for the network to receive information indicating which of the conditional events occurred first to cause or trigger the conditional reconfiguration. In another aspect, the additional SCG failure information may include a time or duration between the fulfillment of different conditional events or triggering conditions. For example, the additional SCG failure information may include or indicate the time between the first conditional event occurring and the last conditional event occurring. In another aspect, the additional SCG failure information may include the time between the first conditional event and the second conditional event, and the time between the second conditional event and the last conditional event to occur.

At step1260, the first MN105A transmits, to the UE115based on the SCG failure information transmitted at step1245indicating additional SCG failure information is available, an information request. In some aspects, the information request may include a UEInformationRequest message including or indicating an additional SCG failure information request. In some aspects, the UEInformationRequest message may comprise a RRC message or IE.

At step1265, the UE115transmits, to the first MN105A, a UE information response or report based on the information request transmitted at step1260. In some aspects, the UE information response includes a UEInformationResponse message including or indicating an additional SCG failure report. In some aspects, the UEInformationResponse message may comprise a RRC message or IE.

At step1270, the first MN105A transmits, to the S-SN105C, an SCG failure report including the additional SCG failure information. In some aspects, the SCG failure may include a Xn message indicating the SPC information transmitted at step1265. In some aspects, the SCG failure report transmitted at step1270may have a similar or identical format as the SCG failure report transmitted at step1250. In other aspects, a new report or report format may be configured for reporting the additional SCG failure information.

In the illustrated example, the UE115stores the additional SCG failure information and reports the additional SCG failure information based on a request from the network. In another example, the UE115may report the additional SCG failure information automatically, and not in response to a request for the additional information. In another aspect, upon detecting a different SCG failure, the previous stored additional SCG failure information may be overwritten with new additional SCG failure information. In some aspects, the UE115may store the additional SCG failure information in a configured variable. In some aspects, the UE115may store the additional SCG failure information for 24 hours, 48 hours, 72 hours, or any other suitable amount of time, greater or smaller. In another aspect, the UE115may store the additional SCG failure information until it is retrieved.

The UE115may indicate that the additional SCG failure information is available via a RRC message, in some aspects. For example, the UE115may indicate that the SCG failure information is available using one or more of a RRCSetupComplete message, a RRCResumeComplete message, a RRCReestablishmentComplete message, and/or a RRCReconfigurationComplete message.

At step1275, based on the SPC report, the MN105A performs one or more network optimizations.

In some aspects, the S-SN105C may correlate information from the SPC report and the SCG failure information, and use the correlated information to perform the network optimizations. In some aspects, the S-SN105C may correlate the SPC report and the SCG failure information based on UE context associated with the SPC report and the SCG failure information. In other instances, the UE context may not be available. For example, the S-SN105C may periodically delete the UE context such that the SPC report and the SCG failure information may not be correlated by UE context. In some aspects, the S-SN105C may be configured to correlate the SPC report and the SCG failure information based on one or more other identifiers or indicators in at least one of the SPC report and/or the SCG failure information.

For example, in some aspects, the SCG failure information may include a SPC report indicator indicating that the SPC report has been sent to the network for the handover and/or SN change. In another example, the SCG failure information may include a SPC Report indicator indicating that there is an SPC report associated with the handover. In another example, the SPC report and the SCG failure information may include or indicate a same C-RNTI. In another aspect, the S-SN105C may correlate the SCG failure information and the SPC report based on their associated timestamps. For example, the S-SN105C may determine that the SPC report is correlated with SCG failure information that is received within a time threshold of the SPC report. In another aspect, the S-SN105C may merge the SPC report with the SCG failure information if the SPC report has not been sent by the time the SCG failure information is generated. In another aspect, the S-SN105C may merge the SCG failure information with the SPC report if the SCG failure information has not been sent by the time the SPC report is generated. In another aspect, if the SCG failure occurs within a certain time window after the generation of the SPC report, the S-SN105C may discard the SPC report. In another aspect, the UE115may add a tag or reference indicator to the SPC report and to the SCG failure information. The reference indicator may be used to correlate the SPC report and the SCG failure information.

FIG.13is a block diagram of an exemplary UE1300according to some aspects of the present disclosure. The UE1300may be a UE115discussed inFIG.1Aor a UE215discussed inFIG.2. As shown, the UE1300may include a processor1302, a memory1304, a PScell change module1308, a transceiver1310including a modem subsystem1312and a radio frequency (RF) unit1314, and one or more antennas1316. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The PScell change module1308may be implemented via hardware, software, or combinations thereof. For example, the PScell change module1308may be implemented as a processor, circuit, and/or instructions1306stored in the memory1304and executed by the processor1302. In some instances, the PScell change module1308can be integrated within the modem subsystem1312. For example, the PScell change module1308can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem1312.

The PScell change module1308may be used for various aspects of the present disclosure, for example, aspects ofFIGS.4-12. The PScell change module1308may coordinate with the processor1302to obtain channel measurements of one or more cells in a master cell group (MCG) and/or in a secondary cell group (SCG). The PScell change module1308may be further configured to receive a successful PScell change (SPC) report configuration, and transmit a SPC report to the network based on the SPC report configuration. The PScell change module1308may be configured to detect a successful PScell change, and transmit the SPC report based on the SPC report configuration and the detecting the successful PScell change. In another aspect, the PScell change module1308may be configured to detect a SCG failure during and/or after the PScell change. The PScell change module1308may be configured to detect the SCG failure based on one or more SCG failure conditions or events, such as the expiration of a configured timer, a radio link failure, and/or any other suitable SCG failure condition. The PScell change module1308may be configured to transmit a SCG failure report to one or more network nodes. The PScell change module1308may be configured to store and report additional SCG failure information to the network. For example, the PScell change module1308may be configured to report a first-occurring triggering event or condition associated with the SCG failure and transmit an additional SCG failure report to the network indicating the additional SCG failure information.

As shown, the transceiver1310may include the modem subsystem1312and the RF unit1314. The transceiver1310can be configured to communicate bi-directionally with other devices, such as the BS s105. The modem subsystem1312may be configured to modulate and/or encode the data from the memory1304and/or the PScell change module1308according to a modulation and coding scheme (MCS), e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a polar coding scheme, a digital beamforming scheme, etc. The RF unit1314may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data (e.g., uplink data, synchronization signal, SSBs) from the modem subsystem1312(on outbound transmissions) or of transmissions originating from another source such as a UE115or a BS105. The RF unit1314may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver1310, the modem subsystem1312and the RF unit1314may be separate devices that are coupled together at the UE115to enable the UE115to communicate with other devices.

The RF unit1314may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas1316for transmission to one or more other devices. The antennas1316may further receive data messages transmitted from other devices. The antennas1316may provide the received data messages for processing and/or demodulation at the transceiver1310. The transceiver1310may provide the demodulated and decoded data (e.g., reference signal, synchronization signal, SSBs) to the PScell change module1308for processing. The antennas1316may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit1314may configure the antennas1316. In some aspects, the RF unit1314may include various RF components, such as local oscillator (LO), analog filters, and/or mixers. The LO and the mixers can be configured based on a certain channel center frequency. The analog filters may be configured to have a certain passband depending on a channel BW. The RF components may be configured to operate at various power modes (e.g., a normal power mode, a low-power mode, power-off mode) and may be switched among the different power modes depending on transmission and/or reception requirements at the UE1300.

In some aspects, the transceiver1310is configured to receive a measurement configuration from the BS, the measurement configuration comprising the first signal measurement offset and a plurality of predetermined parameters. In some aspects, the UE receives the measurement configuration in a radio resource control (RRC) message. The transceiver1310is also configured to communicate, with the BS in a first subband of a plurality of subbands, a measurement report comprising indication of the occurrence of the specified measurement event for initiating a handover of the UE between the BS and the one or more neighbor cells.

In an aspect, the UE1300can include multiple transceivers1310implementing different RATs (e.g., NR and LTE). In an aspect, the UE1300can include a single transceiver1310implementing multiple RATs (e.g., NR and LTE). In an aspect, the transceiver1310can include various components, where different combinations of components can implement different RATs.

FIG.14is a block diagram of an exemplary network node1400according to some aspects of the present disclosure. The network node1400may be a BS105in the network100as discussed above inFIG.1Aor a BS205in the network200as discussed above inFIG.2. As shown, the network node1400may include a processor1402, a memory1404, a PScell change module1408, a transceiver1410including a modem subsystem1412and a RF unit1414, and one or more antennas1416. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The memory1404may include a cache memory (e.g., a cache memory of the processor1402), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some aspects, the memory1404may include a non-transitory computer-readable medium. The memory1404may store instructions1406. The instructions1406may include instructions that, when executed by the processor1402, cause the processor1402to perform operations described herein, for example, aspects ofFIGS.1A-4and7-9. Instructions1406may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement(s) as discussed above with respect toFIG.3.

The PScell change module1408may be implemented via hardware, software, or combinations thereof. For example, the PScell change module1408may be implemented as a processor, circuit, and/or instructions1406stored in the memory1404and executed by the processor1402. In some instances, the PScell change module1408can be integrated within the modem subsystem1412. For example, the PScell change module1408can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem1412.

The PScell change module1408may be implemented via hardware, software, or combinations thereof. For example, the PScell change module1408may be implemented as a processor, circuit, and/or instructions1406stored in the memory1404and executed by the processor1402. In some examples, a BS may include the PScell change module1408.

The PScell change module1408may be used for various aspects of the present disclosure, for example, aspects ofFIGS.4-12. The PScell change module1408may coordinate with the processor1302to receive channel measurements from the UE of one or more cells in a master cell group (MCG) and/or in a secondary cell group (SCG). The PScell change module1408may be further configured to transmit a successful PScell change (SPC) report configuration, and receive a SPC report from a UE based on the SPC report configuration. The PScell change module1408may be configured to receive the SPC report from the UE, where the report is based on the SPC report configuration. In another aspect, the PScell change module1408may be configured to receive a SCG failure report from the UE directly, or via one or more other network nodes. The PScell change module1408may be configured to store SCG failure information and/or SPC information. For example, the PScell change module1408may be configured to report a first-occurring triggering event or condition associated with the SCG failure and receive an additional SCG failure report indicating the additional SCG failure information.

In some aspects, the PScell change module1408may be configured to correlate a SPC report and a SCG failure report based on UE context associated with the SPC report and the SCG failure report. In another aspect, the PScell change module1408may be configured to correlate the SPC report and the SCG failure report based on one or more indicators in the SPC report and/or in the SCG report. In another aspect, the PScell change module1408may be configured to correlate the SPC report and the SCG failure report based on a timing of the SPC report and/or of the SCG report. In some aspects, the PScell change module1408may be configured to configure a UE for SPC reporting. In some aspects, the SPC reporting configuration may indicate one or more timer thresholds, such as a T304 timer threshold, a T310 timer threshold, and/or a T312 timer threshold for the UE to determine or detect a successful PScell change. In other aspects, the PScell change module1408may be configured to determine a portion of the SPC reporting configuration. In some aspects, the PScell change module1408may be configured to aggregate SPC reporting configuration parameters determined by the PScell change module1408and at least one other network node, and transmit a SPC reporting configuration including the aggregated SPC reporting parameters.

As shown, the transceiver1410may include the modem subsystem1412and the RF unit1414. The transceiver1410can be configured to communicate bi-directionally with other devices, such as the UEs115and/or500and/or another core network element. The modem subsystem1412may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a polar coding scheme, a digital beamforming scheme, etc. The RF unit1414may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data (e.g., PDCCH, PDSCH, SSBs, UE reporting configuration, machine learning-based network configuration) from the modem subsystem1412(on outbound transmissions) or of transmissions originating from another source such as a UE115and/or UE500. The RF unit1414may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver1410, the modem subsystem1412and/or the RF unit1414may be separate devices that are coupled together at the BS105to enable the BS105to communicate with other devices.

The RF unit1414may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas1416for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE115or500according to some aspects of the present disclosure. The antennas1416may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver1410. The transceiver1410may provide the demodulated and decoded data (e.g., CBR reports and/or CR reports) to the PScell change module1408for processing. The antennas1416may include multiple antennas of similar or different designs in order to sustain multiple transmission links.

In an aspect, the network node1400can include multiple transceivers1410implementing different RATs (e.g., NR and LTE). In an aspect, the network node1400can include a single transceiver1410implementing multiple RATs (e.g., NR and LTE). In an aspect, the transceiver1410can include various components, where different combinations of components can implement different RATs.

FIG.15is a flow diagram of a wireless communication method1500according to some aspects of the present disclosure. Aspects of the method1500can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device may include a MN105A,105B, or a SN105C,105D. The wireless communication device may comprise the network node1400and may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the steps of method1500. As illustrated, the method1500includes a number of enumerated steps, but aspects of the method1500may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

At step1510, a first network unit transmits, to a second network unit, an indication of a primary secondary group cell (PScell) change (SPC) associated with a user equipment (UE). In some aspects, the first network unit comprises a master node (MN). In another aspect, the first network unit comprises a secondary node (SN). In some aspects, the SN may be a source SN (S-SN) or a target SN (T-SN). The second network unit may comprise a SN, or a MN. In some aspects, if the first network unit is a MN, the second network unit may be a SN. In some aspects, transmitting the indication may comprise transmitting a Xn message including or carrying the indication. In some aspects, transmitting the indication of the SPC comprises transmitting at least one of a SN change required message, a SN addition request, a SN addition request acknowledgement, a SN release request, and/or a SN release request acknowledgement. The first network unit may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the actions of step1510.

At step1520, the first network unit transmits, based on the indication of the PScell change, a successful PScell change report (SPC) configuration. In some aspects, transmitting the SPC configuration may comprise transmitting a RRC message. For example, transmitting the SPC configuration may comprise transmitting a RRCReconfiguration message. In another aspect, transmitting the SPC configuration may comprise transmitting the configuration via a Xn message. In some aspects, the transmitting the SPC configuration comprises transmitting the SPC configuration from a MN directly to the UE. In another aspect, the transmitting the SPC configuration may comprise transmitting the SPC configuration, or at least a portion of a SPC configuration, from a SN to a MN via a Xn message. The first network unit may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the actions of step1520.

At step1530, the first network unit receives a SPC report. In some aspects, the SPC report is based on the SPC configuration and SPC information associated with the UE. For example, in some aspects, the UE may obtain SPC information based on the SPC configuration. The SPC information may include, for example, a trigger event or condition being met associated with the SPC procedure. In some aspects, receiving the SPC report comprises receiving the SPC report directly from the UE. In another aspect, receiving the SPC report comprises receiving the SPC report via a network unit, such as a MN or a SN. In some aspect, the receiving the SPC report may comprise receiving a UE information response including or indicating the SPC report. The UE information response may be transmitted by the UE in response to the UE receiving a UE information request. The UE information request may include or indicate a request for the SPC report. In another aspect, the first network unit may be a SN and may receive the SPC report via the MN. The first network unit may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the actions of step1530.

In some aspects, the method1500further includes the first network unit or another network unit performing network optimizations based on the SPC report. For example, in some aspects, the first network unit or a different network unit may update one or more timer thresholds associated with radio link monitoring (RLM) and/or beam failure detection (BFD) of a MCG and/or SCG. In another aspect, the network unit may detect near failure scenarios during a successful PScell change and/or a successful handover (HO). In some aspects, the method1500further includes receiving a SCG failure report from the UE, wherein the SPC report is also received from the UE. The network unit may perform the network optimization based on a correlation of the SCG failure report with the SPC report.

In another aspect, the first network node receives the SPC report from a second MN different from the MN. In some aspects, the performing the network optimization is based on a correlation of the SCG failure report with the successful PScell change report. In some aspects, the first MN or the second MN may perform the network optimization.

In some aspects, the transmitting the indication of the SPC to the second network unit comprises transmitting a SN addition request message to a T-SN. In another aspect, transmitting the SPC report configuration comprises transmitting a SPC-Config, or a RRC message indicating the SPC-Config, to the UE. In some aspects, the SPC report configuration indicates one or more trigger thresholds for one or more timers associated with a MCG and/or a SCG.

In another aspect, the first network node comprises a SN, and the SN transmits the indication of the SPC by transmitting a SN change request to a MN. In some aspects, the transmitting the successful PScell change report configuration comprises transmitting a first SPC report configuration to the MN, and the receiving the SPC report comprises receiving the SPC report form the MN. In some aspects, the SN change request indicates a threshold for a first timer. For example, the SN change request may include or indicate at least one of a T310 timer threshold and/or a T312 timer threshold. In some aspects, the SN determines the threshold. In another aspect, the MN may determine a second timer threshold. For example, the MN may determine at least one of a T304 timer threshold, a T310 timer threshold, and/or a T312 timer threshold. In some aspects, the MN may receive the SN change request indicating the first timer threshold, and may transmit a SPC configuration indicating the first timer threshold and a second timer threshold, such that the SN and the MN contribute to the SPC configuration.

In some aspects, the method1500further comprises receiving a SCG failure report. For example, the MN may receive a SCG failure report from the UE. In another aspect, a SN may receive a SCG failure report from the MN. In SCG failure report may be based on a detection of a SCG failure. In some aspects, receiving the SCG failure report may comprise receiving a SCGFailureInformation information element from the UE. In another aspect, receiving the SCG failure report may include the SN receiving a Xn message indicating the SCG failure information from the MN. In some aspects, the first network node performs a network optimization based on the SCG failure information. In some aspects, the first network node performs a correlation of the SPC report and the SCG failure information, and performs the network optimization based on the correlation. In another aspect, the first network may correlate the SCG failure report and the SPC report based on one or more indicators included in the SCG failure report and/or the SPC report. For example, the SCG failure report may include a first indicator associated with the SPC report, the SPC report may include a second indicator associated with the SCG failure report, or a combination thereof.

FIG.16is a flow diagram of a wireless communication method1600according to some aspects of the present disclosure. Aspects of the method1600can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device may include a first MN105A. The method1600may include one or more aspects of the procedure1100illustrated inFIG.11. The first MN may comprise the network node1400and may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the steps of method1600. As illustrated, the method1600includes a number of enumerated steps, but aspects of the method1600may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

At step1610, the first MN receives, from a second MN, a HO request. In some aspects, the HO request may comprise a Xn message. In some aspects, the second MN may trigger the HO based on a measurement report from a UE. In some aspects, the HO request may comprise an indication to an AMF that a HO is required or triggered. The first MN unit may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the actions of step1610.

At step1620, the first MN transmits, to a first SN, a PScell change request. In some aspects, transmitting the PScell change request comprises transmitting a SN addition request message. In some aspects, the PScell change request may comprise a Xn message. The first MN unit may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the actions of step1620.

At step1630, the first MN receives, from a UE, a first message indicating HO information is available and SPC information is available. In some aspects, the first message may comprise a RRCReconfigurationComplete message. The first MN unit may utilize one or more components, such as the processor1402, the memory1404, the PScell change module1408, the transceiver1410, the modem1412, and the one or more antennas1416, to execute the actions of step1630.

At step1640, the first MN transmits, to the UE based on the first message, at least one request for the HO information and the SPC information. In some aspects, the at least one request may comprise a UEInformationRequest indicating requests for both a successful HO (SHO) report and a SPC report. In another aspect, the at least one request may comprise separate UEInformationRequest messages, each indicating one of a SHO report request or a SPC report request.

At step1650, the first MN receives, from the UE based on the at least one request, a SHO report and a SPC report. In some aspects, the SHO report is triggered by at least one of a threshold of a MCG or SCG. In some aspects, the SHO report indicates the SHO information the SPC report indicates the SPC information. In some aspects, the receiving the SHO report and the receiving the SPC report comprises receiving a single UEInformationResponse. In another aspect, the receiving the SHO report comprises receiving a first UEInformationResponse and the receiving the SPC report comprises receiving a second UEInformationResponse different from the first UEInformationResponse.

FIG.17is a flow diagram of a wireless communication method1700according to some aspects of the present disclosure. Aspects of the method1700can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device may include a UE, such as one of the UEs115. The method1700may include one or more aspects of the procedure1000illustrated inFIG.10. In this regard, the method1700may include a SN initiating and/or otherwise controlling a PScell change with little or no involvement by the MN. The UE may utilize one or more components, such as the processor1302, the memory1304, the PScell change module1308, the transceiver1310, the modem1312, and the one or more antennas1316, to execute the steps of method1700. As illustrated, the method1700includes a number of enumerated steps, but aspects of the method1700may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

At step1710, the UE receives, from a SN, a SN modification indication. In some aspects, receiving the SN modification indication comprises receiving a RRCReconfiguration message indicating a cell reconfiguration for the PScell. However, any suitable type of messaging may be received by the UE, including RRC IEs, MAC-CEs, DCI, and/or any other suitable messaging.

At step1720, the UE receives, from the SN based on the SN modification indication, a SPC report configuration. In some aspects, the receiving the SPC report configuration comprises receiving a RRCReconfiguration message indicating the SPC report configuration. In some aspects, steps1720and1710may comprise receiving the same RRCReconfiguration message indicating both the SN modification and the SPC report configuration. In other aspects, separate messages may be received in steps1710and1720, respectively, indicating the SN modification and the SPC report configuration.

At step1730, the UE transmits a SPC report based on the SPC report configuration and SPC information obtained by the UE. In some aspects, the UE transmits the SPC report to the SN via SRB3. In another aspect, the UE transmits the SPC report to the MN via SRB1, and the MN transmits the SPC report to the SN. In some aspects, the UE may transmit a UEInformationResponse to the MN based on a UEInformationRequest from the MN. In other aspects, the UE may transmit the SPC report directly to the SN in a UL RRC message via SRB3 if SRB 3 is available.

In some aspects, the method1700includes the UE and a network node performing a random access procedure, as described above. In another aspect, the method1700includes the UE transmitting, based on the SN modification indication, a SN reconfiguration indication. For example, the UE may transmit a RRCReconfigurationComplete message to the SN.

FIG.18is a flow diagram of a wireless communication method1800according to some aspects of the present disclosure. Aspects of the method1800can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device may include a UE, such as one of the UEs115. The method1800may include one or more aspects of the procedure1200shown inFIG.12. The UE may utilize one or more components, such as the processor1302, the memory1304, the PScell change module1308, the transceiver1310, the modem1312, and the one or more antennas1316, to execute the steps of method1800. As illustrated, the method1800includes a number of enumerated steps, but aspects of the method1800may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

At step1810, the UE receives, from a network node, an indication for a cell reconfiguration. In some aspects, the indication may include a RRCReconfiguration message indicating a reconfiguration of a PScell or Scell. In some aspects, the UE may receive the indication from a MN. The MN may transmit the indication based on channel measurements obtained and/or reported by the UE. For example, the channel measurements may be reported in a CSI report. The network node may determine that one or more conditions for the cell reconfiguration are met, and may transmit the indication based on the determination. In another aspect, the network node may receive a signal from a different network node, such as a SN, indicating that a SN change is required.

At step1820, the UE detects a failure of the cell reconfiguration. In some aspects, detecting the failure may comprise detecting a SCG failure associated with the cell reconfiguration. In this regard, the SCG failure detection may be associated with or based on a SCG radio link failure, a failure of the SCG reconfiguration with sync, a control plane (e.g., SRB3) failure of the SCG configuration, a SCG integrity check failure, and/or exceeding a maximum UL transmission timing difference.

At step1830, the UE transmits, to the network node based on the detecting the failure, a SCG failure report indicating SCG failure-related information. In some aspects, the UE may transmit a UCI indicating the SCG failure information. In another example, the UE may transmit a MAC-CE indicating the SCG failure information. In some aspects, the SCG failure information includes or indicates which of a plurality of failure conditions occurred. In some aspects, the SCG failure information may indicate a timer expiration, a random access problem, a max RLC re-transmission occurrence, and/or any other suitable information associated with the cell reconfiguration failure.

At step1840, the UE transmits, to the network node, a further SCG failure report indicating additional SCG failure-related information different from the first SCG failure information. In some aspects, the UE may receive a request from the network node to transmit the further SCG failure report, and may transmit the further SCG failure report based on the request. In some aspects, the transmitting the further SCG failure information may comprise transmitting a UE information request indicating the second SCG failure information.

In another aspect, the second SCG failure information comprises at least one of an indication of a first satisfied conditional event for the cell reconfiguration, or a time duration between a first satisfied condition for the cell reconfiguration and a second satisfied condition for the cell reconfiguration. Ain another aspect, the SCG failure report may indicate that the second SCG failure information is available for transmission. The method1800may further include receiving a SCG failure information request from the network node, and the transmitting the further SCG failure report may be based on the SCG failure information request.

EXEMPLARY ASPECTS OF THE DISCLOSURE

The present disclosure also includes and provides the following exemplary aspects:

Aspect 1. A method of wireless communication performed by a first network unit, wherein the method comprises: transmitting, to a second network unit, an indication of a primary secondary cell group cell (PScell) change associated with a user equipment (UE); transmitting, based on the indication, a successful PScell change (SPC) report configuration; and receiving a SPC report, wherein the SPC report is based on the SPC report configuration and SPC information associated with the UE.

Aspect 2. The method of aspect 1, wherein: the first network unit comprises a master node; the second network unit comprises a target secondary node (SN); the transmitting the indication of the SPC to the second network unit comprises transmitting a SN addition request to the target SN; and the transmitting the SPC report configuration comprises transmitting the SPC report configuration to the UE.

Aspect 3. The method of aspect 2, wherein: the SPC report configuration indicates one or more trigger thresholds for one or more timers associated with a Master Cell Group (MCG), a Secondary Cell Group (SCG), or both.

Aspect 4. The method of any of aspects 2-3, further comprising: performing a network optimization based on the SPC report, wherein the performing the network optimization comprises at least one of: updating a timer threshold associated with radio link monitoring (RLM) or Beam failure detection (BFD); or detecting near failure scenarios during a SPC or a successful handover.

Aspect 5. The method of aspect 4, further comprising: receiving, from the UE, a secondary cell group (SCG) failure report; wherein the receiving the SPC report comprises receiving the SPC report from the UE, and wherein the performing the network optimization is based on a correlation of the SCG failure report with the SPC report.

Aspect 6. The method of aspect 4, further comprising: receiving, from the UE, a secondary cell group (SCG) failure report; and wherein the receiving the SPC report comprises receiving the SPC report from a second master node different from the master node, and wherein the performing the network optimization is based on a correlation of the SCG failure report with the SPC report.

Aspect 7. The method of any of aspects 1-6, wherein: the first network unit comprises a secondary node (SN); the transmitting the indication of the PScell change to the second network unit comprises transmitting a SN change request to a master node; the transmitting the SPC report configuration comprises transmitting a first PScell change report configuration to the master node; and the receiving the SPC report comprises receiving the SPC report from the master node.

Aspect 8. The method of aspect 7, wherein: the SN change request indicates a threshold for a first timer, and wherein the SPC report is based on the first PScell change report configuration and a second PScell change report configuration, wherein the second PScell change report configuration indicates a threshold for a second timer associated with a target SN.

Aspect 9. The method of any of aspects 7-8, further comprising: performing a network optimization based on the SPC report.

Aspect 10. The method of aspect 9, further comprising: receiving, from the master node, a secondary cell group (SCG) failure report, wherein the receiving the SPC report comprises receiving the SPC report from the master node, and wherein the performing the network optimization is based on a correlation of the SCG failure report with the SPC report.

Aspect 11. The method of aspect 9, further comprising: receiving, from the master node, a secondary cell group (SCG) failure report, wherein the receiving the SPC report comprises receiving the SPC report from a second master node different from the master node, and wherein the performing the network optimization is based on a correlation of the SCG failure report with the SPC report.

Aspect 12. The method of any of aspects 1-11, further comprising: receiving a secondary cell group (SCG) failure report, wherein: the SCG failure report includes a first indicator associated with the SPC report, the SPC report includes a second indicator associated with the SCG failure report; or a combination thereof; and performing a network optimization based on a correlation of the SCG failure report with the SPC report, wherein the correlation is based on at least one of the first indicator or the second indicator.

Aspect 13. A method of wireless communication performed by a first master node, wherein the method comprises: receiving, from a second master node, a handover (HO) request; transmitting, to a first secondary node (SN), a primary secondary cell group cell (PScell) change request; receiving, from a user equipment (UE), a first message indicating successful HO information is available and SPC information is available; transmitting, to the UE based on the first message, at least one request for the successful HO information and the SPC information; and receiving, from the UE based on the at least one request, a successful HO report indicating the successful HO information and a SPC report indicating the SPC information.

Aspect 14. The method of aspect 13, further comprising: transmitting, to the UE, a successful HO report configuration indicating one or more trigger thresholds for one or more timers associated with at least one of a master cell group (MCG) or a secondary cell group (SCG), wherein the successful HO report is based on the successful HO report configuration.

Aspect 15. A method of wireless communication performed by a user equipment (UE), wherein the method comprises: receiving, from a secondary node (SN), an SN modification indication; receiving, from the SN based on the SN modification indication, a successful primary secondary cell group cell (PScell) change report configuration; and transmitting a SPC report, wherein the SPC report is based on the SPC report configuration and PScell change information associated with the UE.

Aspect 16. The method of aspect 15, wherein the transmitting the SPC report comprises transmitting the SPC report to a master node in communication with the SN.

Aspect 17. The method of aspect 15, wherein the transmitting the SPC report comprises transmitting the SPC report to the SN.

Aspect 18. A method of wireless communication performed by a user equipment (UE), wherein the method comprises: receiving, from a network node, a reconfiguration message for a PSCell change; detecting, based on the reconfiguration message, a PSCell change failure ; transmitting, to the network node based on the detecting the failure, a secondary cell group (SCG) failure report indicating SCG failure-related information; and transmitting, to the network node after the transmitting the SCG report, a further SCG failure report indicating additional SCG failure-related information.

Aspect 19. The method of aspect 18, wherein the further SCG failure report comprises at least one of: an indication of a first satisfied condition associated with the reconfiguration message for PSCell change; or a time duration between a first satisfied condition and a second satisfied condition associated with the reconfiguration message for PSCell change.

Aspect 20. The method of any of aspects 18-19, wherein: the UE indicates in at least one of the SCG failure report or the further SCG failure report that the additional SCG failure-related information is available for transmission; the method further comprises: receiving, from the network node, an additional SCG failure information request; and the transmitting the additional SCG failure report is based on the receiving the SCG failure information request.

Aspect 21. A first network unit comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the first network unit is configured to perform the actions of any of aspects 1-12.

Aspect 22. A first master node comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the first master node is configured to perform the actions of any of aspects 13-14.

Aspect 23. A UE comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the UE is configured to perform the actions of any of aspects 15-17.

Aspect 24. A UE comprises: a memory device; a transceiver; and a processor in communication with the processor and the transceiver, wherein the UE is configured to perform the actions of any of aspects 18-20.

Aspect 25. A non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a first network unit, wherein the instructions comprise code for causing the first network unit to perform the actions of any of aspects 1-12.

Aspect 26. A non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a first master node, wherein the instructions comprise code for causing the first master node to perform the actions of any of aspects 13-14.

Aspect 27. A non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a UE, wherein the instructions comprise code for causing the UE node to perform the actions of any of aspects 15-17.

Aspect 28. A non-transitory, computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a UE, wherein the instructions comprise code for causing the UE node to perform the actions of any of aspects 18-20.

Aspect 29. A first network unit comprising means for performing actions of any of aspects 1-12.

Aspect 30. A first master node comprising means for performing actions of any of aspects 13-14.

Aspect 31. A UE comprising means for performing actions of any of aspects 15-17.

Aspect 32. A UE comprising means for performing actions of any of aspects 18-20.