SYSTEM AND METHOD FOR OPTIMIZING A PROCESS FOR CHANGE A PRIMARY CELL IN A SECONDARY CELL GROUP - Patent application

Abstract

Presented is a system, method, apparatus, or computer-readable medium for optimizing a primary cell (PSCell) change process for a secondary cell group. A wireless communication device may identify a failure that occurred with respect to a procedure for changing from a first PSCell in a source secondary communication node to a second PSCell in a target secondary communication node. The wireless communication device may transmit a first message including first information related to the failure.

Description

[Technical Field]

[0001] The present disclosure relates generally to wireless communications, including, but not limited to, systems and methods for optimizing a primary cell (PSCell) change process within a secondary cell group. [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP®), a standards organization, is currently working on the specification of a new air interface called 5G New Radio (5G NR) and the Next Generation Packet Core Network (NG-CN or NGC). 5G NR will have three major components: a 5G Access Network (5G-AN), a 5G Core Network (5GC), and a User Equipment (UE). To facilitate the enablement of different data services and requirements, elements of the 5GC, also called network functions, have been simplified, with some of them being software-based so that they can be adapted according to need. Summary of the Invention [Means for solving the problem]

[0003] The exemplary embodiments disclosed herein are directed to solving problems associated with one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings. According to various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. It will be understood, however, that these embodiments are presented by way of example, and not limitation, and that various modifications to the disclosed embodiments can be made while remaining within the scope of the present disclosure, as will be apparent to those skilled in the art upon perusal of this disclosure.

[0004] At least one aspect is directed to a system, method, apparatus, or computer-readable medium for optimizing a primary cell (PSCell) change process for a secondary cell group. A main communication node may receive a first message from a wireless communication device, the first message including first information related to a failure that occurred in connection with a procedure for changing from a first PSCell in a source secondary communication node to a second PSCell in a target secondary communication node. The main communication node may transmit a second message to the source or target secondary communication node that the failure occurred, the second message including a report with the second information.

[0005] In some embodiments, the first information may include at least one of information of the first PSCell, information of the cell in which the failure occurred, whether it is the first PSCell or the second PSCell, the type of failure, measurements on the first PSCell and / or the second PSCell, an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Addition and Modification (CPAC) candidate PSCell, a timer associated with the failure, one or more most recently received CPAC execution conditions, or a list of one or more most recently configured CPAC candidate PSCells.

[0006] In some embodiments, the second information may include at least one of a cell group identification (CGI) of the first PSCell, a CGI of the cell in which the failure occurred, which may be the first PSCell or the second PSCell, a container further including the first information, a maximum number of PSCells to prepare, a list of candidate PSCells, or an arrival probability, by which the wireless communication device is directed to the target secondary communication node.

[0007] At least one other aspect is directed to a system, method, apparatus, or computer-readable medium for optimizing a primary cell (PSCell) change process of a secondary cell group. A source secondary communication node may receive a third message from a wireless communication device, the third message including third information related to a failure that occurred with respect to a procedure for changing from a first PSCell in the source secondary communication node to a second PSCell in a target secondary communication node. The target secondary communication node may transmit a sixth message to a main communication node, the sixth message including a report with sixth information.

[0008] In some embodiments, the fifth information may include at least one of information of the first PSCell, information of the cell in which the failure occurred that is the first PSCell, the type of failure, measurements on the first PSCell and / or the second PSCell, an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Change (CPAC) candidate PSCell, a timer associated with the failure, one or more most recently received CPAC execution conditions, or a list of one or more most recently configured CPAC candidate PSCells.

[0009] In some embodiments, the sixth information may include at least one of a cell group identification (CGI) of the first PSCell, a CGI of the cell in which the failure occurred that is the first PSCell, a container further including the first information, a maximum number of PSCells to prepare, a list of candidate PSCells, or an arrival probability that the wireless communication device is heading towards the target secondary communication node.

[0010] At least one other aspect is directed to a system, method, apparatus, or computer-readable medium for optimizing a primary cell (PSCell) change process for a secondary cell group. A wireless communication device may identify a failure that occurred with respect to a procedure for changing from a first PSCell in a source secondary communication node to a second PSCell in a target secondary communication node. The wireless communication device may transmit a first message including first information related to the failure.

[0011] In some embodiments, the first information may include at least one of information of the first PSCell, information of the cell in which the failure occurred, whether it is the first PSCell or the second PSCell, the type of failure, measurements on the first PSCell and / or the second PSCell, an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Addition and Modification (CPAC) candidate PSCell, a timer associated with the failure, one or more most recently received CPAC execution conditions, or a list of one or more most recently configured CPAC candidate PSCells.

[0012] In some embodiments, the wireless communication device may transmit a first message to a main communication node, and in response to receiving the first message, the main communication node may analyze the first information, generate a report related to the failure including the second information, and transmit a second message including the report to a source or target secondary communication node where the failure occurred.

[0013] In some embodiments, the wireless communication device may transmit a first message to a source secondary communication node. In some embodiments, in response to receiving the first message, the source secondary communication node may analyze the first information, generate a report related to the failure including the second information, and transmit a third message including the report to the main communication node. The report may further be transmitted to a target secondary communication node where the failure occurred.

[0014] In some embodiments, the wireless communication device may transmit a first message to the target secondary communication node. In some embodiments, in response to receiving the first message, the target secondary communication node may analyze the first information, generate a report related to the failure including the second information, and transmit a fourth message including the report to the main communication node. In some embodiments, the report may further be transmitted to the source secondary communication node where the failure occurred.

[0015] In some embodiments, the second information may include at least one of a cell group identification (CGI) of the first PSCell, a CGI of the cell in which the failure occurred, which may be the first PSCell or the second PSCell, a container further including the first information, a maximum number of PSCells to prepare, a list of candidate PSCells, or an arrival probability, by which the wireless communication device is directed to the target secondary communication node. [Brief explanation of the drawings]

[0016] Various exemplary embodiments of the present solution are described in detail below with reference to the following figures or drawings. The drawings are provided for illustrative purposes only and merely depict exemplary embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be considered as limiting the scope, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, the drawings are not necessarily drawn to scale.

[0017] [Figure 1] FIG. 1 illustrates an example cellular communication network in which the techniques disclosed herein may be implemented, according to certain embodiments of the present disclosure.

[0018] [Figure 2] FIG. 2 illustrates a block diagram of an example base station and user equipment device, in accordance with some embodiments of the present disclosure.

[0019] [Figure 3] FIG. 3 illustrates a communication diagram of a process for generating secondary cell group (SCG) failure information for conditional secondary cell group primary cell (PSCell) addition and modification (CPAC), according to an illustrative embodiment.

[0020] [Figure 4] FIG. 4 illustrates a communication diagram of a process for forwarding a secondary cell group (SCG) failure report between a master node (MN) and a secondary node (SN) where the failure occurred, according to an example embodiment.

[0021] [Figure 5] FIG. 5 illustrates a communication diagram of a process for forwarding a secondary cell group (SCG) failure report between a master node (MN), a source secondary node (SN), and the SN where the failure occurred, in accordance with an illustrative embodiment.

[0022] [Figure 6] FIG. 6 illustrates a communication diagram of a process for forwarding a secondary cell group (SCG) failure report between a master node (MN), a secondary node (SN) where the failure occurred, and a target SN, in accordance with an illustrative embodiment.

[0023] [Figure 7] FIG. 7 illustrates a flow diagram of a method for optimizing a primary cell (PSCell) change process for a secondary cell group, according to an illustrative embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Detailed Description Various exemplary embodiments of the present solution are described below with reference to the accompanying figures to enable those skilled in the art to make and use the present solution. As will be apparent to those skilled in the art after reading this disclosure, various changes or modifications of the examples described herein can be made without departing from the scope of the present solution. Thus, the present solution is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, any specific order or hierarchy of steps in the methods disclosed herein is merely an example approach. Based on design preferences, the specific order or hierarchy of steps in a disclosed method or process can be rearranged while remaining within the scope of the present solution. Thus, those skilled in the art will understand that the methods and techniques disclosed herein present various steps or acts in a sample order, and that the present solution is not limited to the specific order or hierarchy presented, unless expressly stated otherwise.

[0025] 1. Mobile communication technology and environment 1 illustrates an exemplary wireless communication network and / or system 100 in which the techniques disclosed herein may be implemented, according to embodiments of the present disclosure. In the discussion that follows, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as “network 100.” Such exemplary network 100 includes a base station 102 (hereinafter “BS 102,” also referred to as a wireless communication node), user equipment devices 104 (hereinafter “UE 104,” also referred to as a wireless communication device), and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 overlaying a geographic area 101, which may communicate with each other via communication links 110 (e.g., wireless communication channels). In FIG. 1, the BS 102 and the UE 104 are contained within the respective geographic boundaries of the cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating in its allocated bandwidth and providing adequate radio coverage to its intended users.

[0026] For example, the BS 102 may operate within an allocated channel transmission bandwidth to provide adequate coverage to the UE 104. The BS 102 and the UE 104 may communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127, which may include data symbols 122 / 128. In this disclosure, the BS 102 and the UE 104 are generally described herein as non-limiting examples of “communication nodes” that may practice the methods disclosed herein. Such communication nodes may be capable of wireless and / or wired communication, according to various embodiments of the present solution.

[0027] 2 illustrates a block diagram of an exemplary wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) in accordance with some embodiments of the present solution. System 200 may include components and elements configured to support known or conventional operational features that need not be described in detail herein. In one illustrative embodiment, system 200 can be used to communicate (e.g., transmit and receive) data symbols within a wireless communication environment, such as wireless communication environment 100 of FIG. 1, as described above.

[0028] The system 200 generally includes a base station 202 (hereinafter “BS 202”) and a user equipment device 204 (hereinafter “UE 204”). The BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled and interconnected, as needed, with each other via a data communication bus 220. The UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled and interconnected, as needed, with each other via a data communication bus 240. The BS 202 communicates with the UE 204 via a communication channel 250, which may be any wireless channel or other medium suitable for the transmission of data as described herein.

[0029] As will be understood by those skilled in the art, system 200 may further include any number of modules other than those shown in FIG. 2 . Those skilled in the art will understand that the various illustrative blocks, modules, circuits, and processing logic described in connection with the embodiments disclosed herein may be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, the various illustrative components, blocks, modules, circuits, and steps are described generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software may depend on the particular application and design constraints imposed on the overall system. Those familiar with the concepts described herein may implement such functionality in a suitable manner for each particular application, but such implementation decisions should not be interpreted as limiting the scope of the present disclosure.

[0030] According to some embodiments, the UE transceiver 230 may be referred to herein as an “uplink” transceiver 230, including a radio frequency (RF) transmitter and an RF receiver, each with circuitry coupled to the antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in a time-duplexed manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a “downlink” transceiver 210, including an RF transmitter and an RF receiver, each with circuitry coupled to the antenna 212. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time-duplexed manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the downlink transmitter is coupled to the downlink antenna 212 at the same time that the uplink receiver circuitry is coupled to the uplink antenna 232 for reception of transmissions over the wireless transmission link 250. Conversely, the operation of the two transceivers 210 and 230 may be coordinated in time such that the uplink transmitter is coupled to the uplink antenna 232 at the same time that the downlink receiver is coupled to the downlink antenna 212 for reception of transmissions over the wireless transmission link 250. In some embodiments, there is close time synchronization, with minimal guard time between duplex direction changes.

[0031] The UE transceiver 230 and the base station transceiver 210 are configured to communicate over a wireless data communication link 250 and cooperate with suitably configured RF antenna arrays 212 / 232 that may support a particular wireless communication protocol and modulation scheme. In some demonstrative embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards and the like. However, it should be understood that the present disclosure is not necessarily limited in application to a particular standard and associated protocol. Rather, the UE transceiver 230 and the base station transceiver 210 may be configured to support alternative or additional wireless data communication protocols, including future standards or variations thereof.

[0032] According to various embodiments, the BS 202 may be, for example, an evolved NodeB (eNB), a serving eNB, a target eNB, a femto station, or a pico station. In some embodiments, the UE 204 may be embodied in various types of user devices, such as a mobile phone, a smartphone, a personal digital assistant (PDA), a tablet, a laptop computer, a wearable computing device, etc. The processor modules 214 and 236 may be implemented or realized with a general-purpose processor, an associative memory, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. As such, a processor may be realized as a microprocessor, a controller, a microcontroller, a state machine, or the like. A processor may also be implemented as a combination of computing devices, e.g., a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.

[0033] Furthermore, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in hardware, firmware, software modules, or any practical combination thereof, executed directly by processor modules 214 and 236, respectively. Memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 may be coupled to processor modules 210 and 230, respectively, such that processor modules 210 and 230 may read information from and write information to memory modules 216 and 234, respectively. Memory modules 216 and 234 may also be integrated within their respective processor modules 210 and 230. In some embodiments, memory modules 216 and 234 may each include cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by processor modules 210 and 230, respectively. Memory modules 216 and 234 may each include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0034] The network communications module 218 generally represents the hardware, software, firmware, processing logic, and / or other components of the base station 202 that enable bidirectional communications between the base station transceiver 210 and other network components and communication nodes configured to communicate with the base station 202. For example, the network communications module 218 may be configured to support Internet or WiMAX traffic. In a typical deployment, without limitation, the network communications module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 may communicate with conventional Ethernet-based computer networks. As such, the network communications module 218 may include a physical interface for connection to a computer network (e.g., a mobile switching center (MSC)). As used herein with respect to specified operations or functions, the terms “configured for,” “configured to,” and variations thereof, refer to devices, components, circuits, structures, machines, signals, etc. that are physically constructed, programmed, formatted, and / or arranged to perform the specified operations or functions.

[0035] The Open Systems Interconnection (OSI) model (referred to herein as the "Open Systems Interconnection Model") is a conceptual and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that open the system to interconnect and communicate with other systems. The model is divided into seven subcomponents or layers, each representing a conceptual collection of services provided to the layers above and below it. The OSI model also defines logical networks and effectively describes computer packet transfers by using different layer protocols. The OSI model may also be referred to as the seven-layer OSI model or seven-layer model. In some embodiments, the first layer may be the physical layer. In some embodiments, the second layer may be the medium access control (MAC) layer. In some embodiments, the third layer may be the radio link control (RLC) layer. In some embodiments, the fourth layer may be the packet data convergence protocol (PDCP) layer. In some embodiments, the fifth layer may be the radio resource control (RRC) layer. In some embodiments, the sixth layer may be a non-access stratum (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer may be another layer.

[0036] 2. SYSTEM AND METHOD FOR OPTIMIZING THE PRIMARY AND SECONDARY CELL CHANGE PROCESS The primary cell (PSCell) change procedure for a conditional secondary cell group between secondary nodes (SNs) may be performed according to a protocol. However, abnormal cases related to this procedure cannot be identified and recovered autonomously. Presented herein are systems and methods that optimize the PSCell change process to address these technical challenges.

[0037] In such settings, a self-optimizing network (SON) within a long-term evolution (LTE) system may be used to support the deployment of the system and performance optimization. Mobility robustness optimization (MRO) may be one of the most prominent features within a SON. MRO may aim to detect and enable correction of mobility-related issues, such as connection failures due to intra- or inter-Radio Access Technology (RAT) mobility, unnecessary handovers to another RAT, and inter-RAT ping-pong, among others, which would degrade the user experience and waste network resources.

[0038] Multi-Radio Dual Connectivity (MR-DC) may be a generalization of Evolved Universal Terrestrial Radio Access (E-UTRA) Intra-Radio Dual Connectivity (DC). In E-UTRA DC, multiple receiver and transmitter (Rx / Tx)-capable user equipment (UE) may be configured to utilize resources provided by two different nodes connected via a non-ideal backhaul, one providing Novel Radio (NR) access and the other providing either E-UTRA or NR access. One node may act as a Master Node (MN) and the other as a Secondary Node (SN). The MN and SN may be connected via a network interface, and at least the MN may be connected to a core network.

[0039] A conditional PSCell addition may be a PSCell addition procedure that is executed when a PSCell addition condition is met. A conditional PSCell change may be a PSCell change procedure that is executed when a PSCell execution condition is met. An inter-SN conditional PSCell change may be a PSCell change procedure from a source PSCell in a source SN to a target PSCell in a target SN.

[0040] Regarding PSCell change failure, the failure may occur due to the following three cases: (1) changing the PSCell too late, (2) changing the PSCell too early, or (3) changing to the incorrect PSCell. Under the first case, a secondary cell group (SCG) failure may occur after the UE has remained in the PSCell for an extended period of time, and a suitable different PSCell may be found based on measurements reported from the UE. Under the second case, an SCG failure may occur immediately after a successful PSCell change from the source PSCell to the target PSCell, or a PSCell change failure may occur during the PSCell change procedure. The source PSCell may still be the preferred PSCell based on measurements reported from the UE. Under the third case, an SCG failure may occur immediately after a successful PSCell change from the source PSCell to the target PSCell, or a PSCell change failure may occur during the PSCell change procedure. In this case, a suitable PSCell may be different from the source PSCell or a target PSCell may be found based on measurements reported from the UE.

[0041] When a conditional PSCell addition and modification (CPAC) procedure failure occurs, the UE may send SCG failure information to the network to indicate the failure. For MR-DC deployment in an NG-RAN network, the UE may send the SCG failure information to the MN. The MN may then analyze the received SCG failure information and generate an SCG failure information report to the SN where the failure occurred.

[0042] In some embodiments, the UE may transmit SCG failure information to the source SN. The source SN may then analyze the received SCG failure information and generate an SCG failure information report to the MN, which may forward the SCG failure information to the SN where the failure occurred (the target SN). In some embodiments, the UE may transmit SCG failure information to the target SN. The target SN may then analyze the received SCG failure information and generate an SCG failure information report to the MN, which may forward the SCG failure information to the SN where the failure occurred (the source SN).

[0043] A. Occurrence of SCG failure information regarding CPAC 3, depicted is a communication diagram of a process 300 for generating secondary cell group (SCG) failure information for a conditional secondary cell group primary cell (PSCell) addition and modification (CPAC). The process 300 may be for generation of SCG failure information by a UE due to a failure of CPAC performed by the UE 305 and the network 310.

[0044] In step 315, the UE 305 may detect an SCG failure in the network. The SCG failure may be caused by a failure of a CPAC procedure. In step 320, the UE 305 may trigger a radio resource control (RRC) reconfiguration procedure between the UE 305 and the network 310 to select a suitable next generation radio access network (NG-RAN) cell. In step 325, the UE 305 may send SCG failure information to the network 310, indicating detailed information about the SCG failure related to the CPAC.

[0045] More specifically, the SCG failure information related to CPAC includes, among other things, at least one of the following: information of the previous SN cell (previousPSCellId), information of the SN cell in which the failure occurred (failedPSCellId), an SN cause value (SCGFailureType) for an SCG failure such as a CPAC failure, a PSCell measurement value in case of an SCG failure (MeasResultSCG-Failure), an indication of whether the measured PSCell is a CPAC candidate PSCell, an SCG failure timer (timeSCGFailure), the most recently received CPAC execution condition, and a list of the most recently configured CPAC candidate PSCells.

[0046] B. SCG Failure Information Report Transfer Between MN and SN in the First Scenario 4, depicted is a communication diagram of a process 400 for forwarding a secondary cell group (SCG) failure report between a master node (MN) and a secondary node (SN) where the failure occurred. For this scenario, the SCG failure information may be transmitted by the UE 405 to the MN 410, which may forward the SCG failure information report to the SN 415 where the failure occurred.

[0047] In step 420, the UE 405 may transmit SCG failure information related to CPAC to the MN 410. More specifically, the SCG failure information related to CPAC may include, among others, at least one of the following: information of the previous SN cell (previousPSCellId), information of the SN cell where the failure occurred (failedPSCellId), an SN cause value for an SCG failure such as a CPAC failure (SCGFailureType), a PSCell measurement value in case of an SCG failure (MeasResultSCG-Failure), an indication of whether the measured PSCell is a CPAC candidate PSCell, an SCG failure timer (timeSCGFailure), the most recently received CPAC execution condition, and a list of the most recently configured CPAC candidate PSCells.

[0048] In step 425, after receiving the SCG failure information, the MN 410 may analyze the SCG failure information and generate an SCG failure information report. More specifically, the SCG failure information report may include at least one of the following, among others: a source PSCellCGI (cell group identification), a PSCellCGI where the failure occurred, an SCG failure information report container (with the SCG failure information as shown above), a maximum number of PSCells to prepare, a candidate PSCell list, and an arrival probability for the UE towards the candidate target SN.

[0049] In step 430, the MN may send an SCG failure information report to the SN where the failure occurred via XnAP signaling. Furthermore, the SN where the failure occurred 415 may be the SN where the SCG failure occurred. More specifically, the XnAP signaling may be one of the following, among others: an SCG failure information report message, an S-node modification request message, and an S-node addition request message. Using the SCG failure information report, the SN where the failure occurred may be able to identify and recover from the failure.

[0050] C. SCG Failure Information Report Transfer Between MN and SN in the Second Scenario 5, depicted is a communication diagram of a process 500 for forwarding a secondary cell group (SCG) failure report between a master node (MN), a source secondary node (SN), and the SN where the failure occurred. For this scenario, the SCG failure information may be sent directly by the UE 505 to the source SN 515. The source SN 515 may send the SCG failure information report to the MN 510. The MN 510 may forward the SCG failure information report to the SN 520 where the failure occurred. In this scenario, the SCG failure may occur in the target SN.

[0051] In step 525, the UE 505 may transmit SCG failure information related to the CPAC to the source SN 515. More specifically, the SCG failure information related to the CPAC includes, among other things, at least one of the following: information of the previous SN cell (previousPSCellId), information of the SN cell where the failure occurred (failedPSCellId), an SN cause value for the SCG failure such as a CPAC failure (SCGFailureType), a PSCell measurement value in case of an SCG failure (MeasResultSCG-Failure), an indication of whether the measured PSCell is a CPAC candidate PSCell, an SCG failure timer (timeSCGFailure), the most recently received CPAC execution condition, and a list of the most recently configured CPAC candidate PSCells.

[0052] In step 530, after receiving the SCG failure information, the source SN 515 may analyze the SCG failure information and generate an SCG failure information report. More specifically, the SCG failure information report may include, among other things, at least one of the following: a source PSCellCGI (cell group identification), a PSCellCGI where the failure occurred, an SCG failure information report container (with the SCG failure information as shown above), a maximum number of PSCells to prepare, a candidate PSCell list, and an arrival probability for the UE towards the candidate target SN.

[0053] In step 535, the source SN 515 may send an SCG failure information report to the MN 510 via XnAP signaling. More specifically, the XnAP signaling may be one of the following, among others: an S-node modification request message, an S-node change request message, and an SCG failure forwarding message. In step 540, the MN 510 may forward the SCG failure information report to the SN 520 in which the failure occurred. Using the SCG failure information report, the SN 520 in which the failure occurred may be able to identify and recover from the failure.

[0054] D. SCG Failure Information Report Transfer between MN and SN (Scenario 3) Referring now to Figure 6, depicted is a communication diagram of a process 600 for forwarding a secondary cell group (SCG) failure report between a master node (MN), a secondary node (SN) where the failure occurred, and a target SN. For this scenario, the SCG failure information may be sent directly by the UE 605 to the target SN 620. The target SN 620 may send the SCG failure information report to the MN 610. The MN 610 may forward the SCG failure information report to the SN 615 where the failure occurred. In this scenario, the SCG failure may occur within the source SN.

[0055] In step 625, the UE 605 may transmit SCG failure information related to the CPAC to the target SN 620. More specifically, the SCG failure information related to the CPAC may include, among others, at least one of the following: information of the previous SN cell (previousPSCellId), information of the SN cell where the failure occurred (failedPSCellId), an SN cause value for the SCG failure such as a CPAC failure (SCGFailureType), a PSCell measurement value in case of an SCG failure (MeasResultSCG-Failure), an indication of whether the measured PSCell is a CPAC candidate PSCell, an SCG failure timer (timeSCGFailure), the most recently received CPAC execution condition, and a list of the most recently configured CPAC candidate PSCells.

[0056] In step 630, after receiving the SCG failure information, the target SN 620 may analyze the SCG failure information and generate an SCG failure information report. More specifically, the SCG failure information report may include, among other things, at least one of the following: a source PSCellCGI (cell group identification), a PSCellCGI where the failure occurred, an SCG failure information report container (with the SCG failure information as shown above), a maximum number of PSCells to prepare, a candidate PSCell list, and an arrival probability for the UE towards the candidate target SN.

[0057] In step 635, the target SN 620 may send an SCG failure information report to the MN 610 via XnAP signaling. More specifically, the XnAP signaling may be one of the following, among others: an S-node modification request message, an S-node change request message, and an SCG failure forwarding message.

[0058] In step 640, the MN 610 may forward the SCG failure information report to the SN 615 where the failure occurred. Using the SCG failure information report, the SN where the failure occurred may be able to identify the failure and recover from the failure.

[0059] In short, the UE may transmit SCG failure information related to the CPAC to the MN. The MN may then analyze the received SCG failure information and generate an SCG failure information report to the SN where the failure occurred. In some embodiments, the UE may transmit SCG failure information related to the CPAC to the source SN. The source SN may then analyze the received SCG failure information and generate an SCG failure information report to the MN, and the MN may forward the SCG failure information to the SN where the failure occurred (target SN). In some embodiments, the UE may transmit SCG failure information related to the CPAC to the target SN. The target SN may then analyze the received SCG failure information and generate an SCG failure information report to the MN, and the MN forwards the SCG failure information to the SN where the failure occurred (source SN).

[0060] Generally, the SCG failure information related to CPAC may include, among others, at least one of the following: information of the previous SN cell (previousPSCellId), information of the SN cell in which the failure occurred (failedPSCellId), an SN cause value for an SCG failure such as a CPAC failure (SCGFailureType), a PSCell measurement value in case of an SCG failure (MeasResultSCG-Failure), an indication of whether the measured PSCell is a CPAC candidate PSCell, an SCG failure timer (timeSCGFailure), the most recently received CPAC execution condition, and a list of the most recently configured CPAC candidate PSCells.

[0061] Furthermore, the SCG failure information report may include, among other things, at least one of the following: source PSCellCGI (cell group identification), PSCellCGI where the failure occurred, SCG failure information report container (with SCG failure information as shown above), maximum number of PSCells to prepare, candidate PSCell list, and arrival probability for the UE towards candidate target SN.

[0062] E. How to Optimize the Primary Cell (PSCell) Change Process in a Secondary Cell Group Referring now to FIG. 7, depicted is a flow diagram of a method 700 for optimizing a primary cell (PSCell) change process of a secondary cell group. The method 700 may be implemented by or performed using any of the components described herein above, such as the UE 104 or 204 or the BS 102 or 202, among others. Under the method 700, a wireless communication device may identify a failure (705). The wireless communication device may transmit a message (710). A main communication node, a source secondary communication node, or a target secondary communication node may receive the message (715, 715′, or 715″). The main communication node, the source secondary communication node, or the target secondary communication node may analyze the information (720, 720′, or 720″). The main communication node, the source secondary communication node, or the target secondary communication node may generate a report (725, 725′, or 725″). The source secondary communication node or the target secondary communication node may transmit a message (730 or 730′). The main communication node may receive the message (735). The main communication node may send the message (740). The target secondary communication node may receive the message (745).

[0063] More specifically, a wireless communication device (e.g., UE 104 or 204) may sense, detect, or otherwise identify a failure (705). The failure may occur with respect to a procedure for changing from a primary cell (PSCell) of a first secondary cell group in a source secondary communication node (e.g., BS 102 or 202) to a second PSCell in a target secondary communication node (e.g., BS 102 or 202). A failure associated with a PSCell change may result from, among other things, (1) a secondary cell group (SCG) failure that occurs after the wireless communication device remains in the PSCell for an extended period of time, (2) an SCG failure that occurs after a successful PSCell change from the source PSCell to the target PSCell, (3) a PSCell change failure that occurs during the PSCell change process itself, (4) an SCG failure that occurs immediately after a successful PSCell change from the source PSCell to the target PSCell, or (5) a PSCell change failure that occurs during the PSCell change procedure. In response to detecting a failure, the wireless communication device may instruct the PSCell to obtain, derive, or otherwise generate information about the failure.

[0064] The wireless communication device may provide, transmit, or otherwise send a message including information about the failure (710). In some embodiments, the wireless communication may send the message to a main communication node (e.g., BS 102 or 202). In some embodiments, the wireless communication device may send the message to a source secondary communication node. In some embodiments, the wireless communication device may send the message to a target secondary communication node. The information about the failure may identify or include, among other things, information about the first PSCell, information about the cell where the failure occurred, whether it be the first PSCell or the second PSCell, the type of failure, measurements on the first PSCell and / or the second PSCell, an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Addition and Modification (CPAC) candidate PSCell, a timer associated with the failure, one or more most recently received CPAC execution conditions, or a list of one or more most recently configured CPAC candidate PSCells.

[0065] The main communication node may read, identify, or receive a message including information related to the failure from the wireless communication device (715). The wireless communication device may transmit the message to the source secondary communication node or to a wireless communication node on behalf of the source secondary communication node. The source secondary communication node may read, identify, or receive a message including information related to the failure from the wireless communication device (715'). The wireless communication device may transmit the message to the source secondary communication node on behalf of the main communication node or the target secondary communication node. The target secondary communication node may read, identify, or receive a message including information related to the failure from the wireless communication device (715''). The wireless communication device may transmit the message to the target secondary communication node on behalf of the main communication node or the source secondary communication node.

[0066] The main communication node may evaluate, process, or otherwise analyze information related to the failure in the message (720). Analysis of the information by the wireless communication node may be in response to receiving the message from the wireless communication device. To analyze, the main communication node may analyze the information in the message and process the information. Based on the information, the main communication node may identify or determine that one of the source secondary communication node or the target secondary communication node is where the failure associated with the PSCell change occurred. From analyzing the information, the main communication node may generate, output, or otherwise generate a report related to the failure (725). If the source secondary communication node is identified as where the failure occurred, the main communication node may decide to send a message including the report to the source secondary communication node. Otherwise, if the target secondary communication node is identified as where the failure occurred, the main communication node may decide to send a message including the report to the target secondary communication node.

[0067] The source secondary communication node may evaluate, process, or otherwise analyze information related to the failure in the message (720'). Analysis of the information by the wireless communication node may be in response to receiving the message from the wireless communication device. To analyze, the source secondary communication node may parse the information in the message and process the information. Based on the information, the source secondary communication node may identify or determine that the target secondary communication node is where the failure associated with the PSCell change occurred. From analyzing the information, the source secondary communication node may generate, output, or otherwise generate a report related to the failure (725'). The source secondary communication node may provide, transmit, or otherwise send a message including the report to the main communication node (730).

[0068] The target secondary communication node may evaluate, process, or otherwise analyze information related to the failure in the message (720'). Analysis of the information by the wireless communication node may be in response to receiving the message from the wireless communication device. To analyze, the target secondary communication node may parse the information in the message and process the information. Based on the information, the target secondary communication node may identify or determine that the source secondary communication node is where the failure associated with the PSCell change occurred. From analyzing the information, the target secondary communication node may generate, output, or otherwise generate a report related to the failure (725'). The target secondary communication node may provide, transmit, or otherwise send a message including the report to the main communication node (730').

[0069] The report may include, among other things, information generated (e.g., by the main wireless communication node, the source secondary communication node, or the target secondary communication node) from analyzing information that may identify or include the cell group identification (CGI) of the first PSCell, the CGI of the cell in which the failure occurred, whether it is the first PSCell or the second PSCell, a container further including the first information, the maximum number of PSCells to prepare, a list of candidate PSCells, or an arrival probability that the wireless communication device is heading towards the target secondary communication node.

[0070] The main communication node may read, identify, or otherwise receive a message from the source secondary communication node or the target secondary communication node (735). In response to receiving the message, the main communication node may analyze the message and extract or identify a report related to the failure, including information. From the information, the main communication node may identify or determine that one of the source secondary communication node or the target secondary communication node is where the failure associated with the PSCell change occurred. If the source secondary communication node is identified as where the failure occurred, the main communication node may decide to send a message including the report to the source secondary communication node. Otherwise, if the target secondary communication node is identified as where the failure occurred, the main communication node may decide to send a message including the report to the target secondary communication node.

[0071] The main communication node may provide, transmit, or otherwise send a message to the source secondary communication node or the target secondary communication node (740). The message may include a report with information from analyzing information related to the failure. If the determination is that the message should be sent to the source secondary communication node, the main communication node may send a message including the report from the target secondary communication node to the source secondary communication node. The source secondary communication node may then read, identify, or otherwise receive the message from the main communication node (745). If the determination is that the message should be sent to the target secondary communication node, the main communication node may send a message including the report from the source secondary communication node to the target secondary communication node. The target secondary communication node may then read, identify, or otherwise receive the message from the main communication node (745').

[0072] While various embodiments of the present solution have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. Similarly, various diagrams may depict example architectures or configurations, which are provided to enable those skilled in the art to understand example features and functionality of the present solution. However, such skilled artisans will understand that the present solution is not limited to the example architectures or configurations shown, but may be implemented using a variety of alternative architectures and configurations. Additionally, as will be understood by those skilled in the art, one or more features of one embodiment can be combined with one or more features of another embodiment described herein. Thus, the scope and scope of the present disclosure should not be limited by any of the example embodiments described above.

[0073] It should also be understood that any reference to elements herein using a designation such as "first," "second," etc., does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some manner.

[0074] Additionally, those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, and symbols that may be referenced in the above description may be represented by, for example, voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0075] Those skilled in the art will further understand that any of the various illustrative logic blocks, modules, processors, means, circuits, methods, and functions described in connection with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementations, analog implementations, or a combination of the two), firmware, various forms of programs or design code incorporating instructions (which may be conveniently referred to herein as “software” or “software modules”), or any combination of these techniques. To clearly illustrate this interchangeability of hardware, firmware, and software, the various illustrative components, blocks, modules, circuits, and steps are described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these techniques, depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure.

[0076] Furthermore, those skilled in the art will understand that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented in or by integrated circuits (ICs), which may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, or any combination thereof. The logic blocks, modules, and circuits may further include antennas and / or transceivers to communicate with various components within a network or device. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration for performing the functions described herein.

[0077] When implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media, including any medium that can enable a computer program or code to be transferred from one place to another. A storage medium can be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0078] As used herein, the term "module," as used herein, refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purposes of discussion, various modules are described as discrete modules. However, as will be apparent to one skilled in the art, two or more modules may be combined to form a single module that performs the associated functions according to embodiments of the present solution.

[0079] Additionally, memory or other storage devices and communication components may be employed in embodiments of the solution. It should be understood that, for purposes of clarity, the above description describes embodiments of the solution with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements, or domains may be used without departing from the solution. For example, functionality illustrated as being performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Hence, references to specific functional units do not indicate a strict logical or physical structure or organization, but merely a reference to a suitable means for providing the described functionality.

[0080] Various modifications of the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as limited in the following claims.

Claims

1. 1. A wireless communication method, comprising: receiving, by a main communication node, from a wireless communication device, a first message including first information related to a failure that occurred in connection with a procedure for changing from a first PSCell in a source secondary communication node to a second PSCell in a target secondary communication node; sending, by said main communication node, to a source or target secondary communication node where said failure occurred, a second message including a report with second information; A method comprising:

2. The first information is Information of the first PSCell; Information of a cell in which a failure occurred, which is the first PSCell or the second PSCell; the type of failure, Measurements relating to the first PSCell and / or the second PSCell; an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Addition and Modification (CPAC) candidate PSCell; a timer associated with said failure; one or more most recently received CPAC execution conditions; or A list of one or more currently configured CPAC candidate PSCells The wireless communication method of claim 1 , comprising at least one of:

3. The second information is a Cell Group Identification (CGI) of the first PSCell; a CGI of a cell in which a failure occurred, the cell being the first PSCell or the second PSCell; a container further including the first information; The maximum number of PSCells to be prepared, a list of candidate PSCells, or The arrival probability of the wireless communication device toward the target secondary communication node The wireless communication method of claim 1 , comprising at least one of:

4. 1. A wireless communication method, comprising: receiving, by a source secondary communication node, from a wireless communication device, a third message including third information related to a failure that occurred in connection with a procedure for changing from a first PSCell in the source secondary communication node to a second PSCell in a target secondary communication node; sending, by the source secondary communication node, to a main communication node, a fourth message including a report with fourth information; A method comprising:

5. The third information is Information of the first PSCell; Information of the cell in which the failure occurred, which is the second PSCell; the type of failure, Measurements relating to the first PSCell and / or the second PSCell; an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Addition and Modification (CPAC) candidate PSCell; a timer associated with said failure; one or more most recently received CPAC execution conditions; or A list of one or more currently configured CPAC candidate PSCells The wireless communication method of claim 4, comprising at least one of:

6. The fourth information is a Cell Group Identification (CGI) of the first PSCell; the CGI of the cell in which the failure occurred, which is the second PSCell; a container further including the first information; The maximum number of PSCells to be prepared, a list of candidate PSCells, or The arrival probability of the wireless communication device toward the target secondary communication node The wireless communication method of claim 4, comprising at least one of:

7. The wireless communication method according to claim 4 , wherein the report is further transmitted from the main communication node to the target secondary communication node where the failure occurred.

8. 1. A wireless communication method, comprising: receiving, by the target secondary communication node, from the wireless communication device, a fifth message including fifth information related to a failure that occurred in connection with a procedure for changing from a first PSCell in the source secondary communication node to a second PSCell in the target secondary communication node; sending, by the target secondary communication node to the main communication node, a sixth message including a report with sixth information; A method comprising:

9. The fifth information is Information of the first PSCell; Information of the cell in which the failure occurred, which is the first PSCell; the type of failure, Measurements relating to the first PSCell and / or the second PSCell; an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Addition and Modification (CPAC) candidate PSCell; a timer associated with said failure; one or more most recently received CPAC execution conditions; or A list of one or more currently configured CPAC candidate PSCells 9. The wireless communication method of claim 8, comprising at least one of:

10. The sixth information is a Cell Group Identification (CGI) of the first PSCell; the CGI of the cell in which the failure occurred, being the first PSCell; a container further including the first information; The maximum number of PSCells to be prepared, a list of candidate PSCells, or The arrival probability of the wireless communication device toward the target secondary communication node 9. The wireless communication method of claim 8, comprising at least one of:

11. The wireless communication method according to claim 8 , wherein the report is further transmitted from the main communication node to the source secondary communication node where the failure occurred.

12. 1. A wireless communication method, comprising: Identifying, by the wireless communication device, a failure that has occurred in a procedure for changing from a first PSCell in a source secondary communication node to a second PSCell in a target secondary communication node; transmitting, by the wireless communication device, a first message including first information related to the failure; A method comprising:

13. The first information is Information of the first PSCell; Information of a cell in which a failure occurred, which is the first PSCell or the second PSCell; the type of failure, Measurements relating to the first PSCell and / or the second PSCell; an indicator indicating whether the first and / or second PSCell being measured is a Conditional PSCell Addition and Modification (CPAC) candidate PSCell; a timer associated with said failure; one or more most recently received CPAC execution conditions; or A list of one or more currently configured CPAC candidate PSCells The wireless communication method of claim 12, comprising at least one of:

14. The wireless communication method of claim 12 , further comprising transmitting the first message by the wireless communication device to a main communication node.

15. In response to receiving the first message, the main communication node: generating a report related to the failure that includes the second information; and sending a second message including said report to said source or target secondary communication node where said failure occurred; The wireless communication method according to claim 14, configured to perform the following:

16. The wireless communication method of claim 12 , further comprising transmitting, by the wireless communication device, the first message to the source secondary communication node.

17. In response to receiving the first message, the source secondary communication node: generating a report related to the failure that includes the second information; and sending a third message to a main communication node containing said report; configured to: The wireless communication method of claim 16 , wherein the report is further transmitted to the target secondary communication node where the failure occurred.

18. The wireless communication method of claim 12 , further comprising transmitting, by the wireless communication device, the first message to the targeted secondary communication node.

19. In response to receiving the first message, the target secondary communication node: generating a report related to the failure that includes the second information; and sending a fourth message to the main communication node including said report; configured to: The wireless communication method of claim 18, wherein the report is further transmitted to the source secondary communication node where the failure occurred.

20. The second information is a Cell Group Identification (CGI) of the first PSCell; a CGI of a cell in which a failure occurred, the cell being the first PSCell or the second PSCell; a container further including the first information; The maximum number of PSCells to be prepared, a list of candidate PSCells, or The arrival probability of the wireless communication device toward the target secondary communication node 20. The wireless communication method of claim 15, 17, or 19, comprising at least one of:

21. A wireless communication device, the wireless communication device comprising a processor and a memory, the processor being configured to read code from the memory and to perform a method according to any of claims 1-20.

22. 21. A computer program product comprising a computer readable program medium code stored thereon, the code, when executed by a processor, causing the processor to perform a method according to any of claims 1-20.

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