Reducing outage user equipment (UE) connected with multi-rat dual connectivity (MRDC)

Abstract

A method for reducing outage user equipment (UE) connected with multi-RAT dual connectivity (MRDC) is disclosed. The method includes receiving, from a plurality of communication nodes, an initial context setup information associated with one or more UEs served by a cluster of the plurality of the communication nodes. The method includes receiving, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs. The method includes in response to receipt of the information associated with one or more neighboring cells, selecting a cell candidate from among the one or more neighboring cells for the UE. The method includes transmitting, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for UE.

Description

REDUCING OUTAGE USER EQUIPMENT (UE) CONNECTED WITH MULTI-RAT DUAL CONNECTIVITY (MRDC)CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to Indian Non-Provisional Patent Application No. 202411082354, filed on October 28, 2024, the entire contents of which are incorporated herein by reference.FIELD

[0002] The present disclosure relates to reducing outage User Equipment (UE) connected with Multi-RAT Dual Connectivity (MRDC).BACKGROUND

[0003] The information disclosed in this background section is only for enhancement of understanding of the general background of the disclosure and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

[0004] Multi -Radio Dual Connectivity (MRDC) is a key feature in today’s wireless communication networks that allows User Equipment (UE) to simultaneously connect to different radio access technologies, such as 5thgeneration (5G) New Radio (NR) and 4thgeneration (4G). This dual connectivity enhances data rates, reduces latency, and improves overall performance.Accordingly, the UE may be connected to a Primary Cell (PCell) belonging to a Master Cell Group (MCG) of a first radio access technologies (RAT), such as 5G, and a Secondary Cell (Scell) belonging to a secondary cell group (SCG) of a first / second RAT. However, if a node corresponding to any of the RATs goes down, all the connected user equipment (UEs) to that eNodeB (eNB) are disconnected. This requires all the UEs to perform a Random Access Channel (RACH) process and attach procedure again to reconnect to the network. The reconnecting process takes time, as UE context is lost when the node goes down, thereby impacting critical services, such as factory automation, robotic, remote surgery, telemedicine, emergency services, and autonomous vehicles, etc. Further, the loss of the UE context may also impact the UEs connected to that node.SUMMARY

[0005] This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the disclosure. This summary is neither intended to identify key or essential inventive concepts of the disclosure nor is it intended for determining the scope of the disclosure.

[0006] According to one embodiment of the present disclosure, an apparatus is disclosed. The apparatus is configured to receive, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes. The apparatus is further configured to receive, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs. The apparatus is also configured to, in response to receipt of the informationassociated with one or more neighboring cells, select a cell candidate from among the one or more neighboring cells for the UE. The apparatus is further configured to transmit, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

[0007] According to one embodiment of the present disclosure, a method is disclosed. The method includes receiving, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes. Further, the method includes receiving, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs. The method further includes in response to receipt of the information associated with one or more neighboring cells, selecting a cell candidate from among the one or more neighboring cells for the UE. The method also includes transmitting, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

[0008] According to one embodiment of the present disclosure, a non-transitory computer- readable medium is disclosed. The non-transitory computer-readable medium storing instructions, the instructions comprising: one or more instructions that, when executed by an apparatus, the apparatus comprising one or more processors, cause the one or more processors to receive, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes. The one or more instructions further cause the one or more processor to receive, from a secondary cell group(SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs. The one or more instructions further cause the one or more processor to, in response to receipt of the information associated with one or more neighboring cells, select a cell candidate from among the one or more neighboring cells for the UE. The one or more instructions further cause the one or more processor to transmit, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

[0009] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope. The disclosure will be described and explained with additional specificity and detail in the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Features, aspects, and advantages of embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements, and wherein:

[0011] FIG. 1 illustrates an architecture of a wireless communication network, according to related art;

[0012] FIG. 2 illustrates an O-RAN architecture associated with RICs (near-RT RIC and non-RRIC) in a communication network, according to an embodiment of the present disclosure;

[0013] FIG. 3 illustrates a schematic block diagram of the near-RT RIC for maintaining connection between a UE and a communication node in MRDC mode, according to an embodiment of the present disclosure;

[0014] FIG. 4 illustrates a schematic operational flow diagram of the plurality of modules of the apparatus, in accordance with an embodiment of the present disclosure;

[0015] FIG. 5 illustrates a signal flow diagram of reception of initial context setup information, according to an embodiment of the present disclosure;

[0016] FIG. 6 illustrates a signal flow diagram of reception of information associated with neighboring cells, according to an embodiment of the present disclosure;

[0017] FIG. 7 illustrates a signal flow diagram of transmission of the initial context setup information to a target node, according to an embodiment of the present disclosure;

[0018] FIG. 8 illustrates a flow diagram depicting a method for maintaining a connection between the UE and the communication node in MRDC mode, according to an embodiment of the present disclosure; and

[0019] FIG. 9 illustrates a diagram of example components of a wireless communication device, according to an embodiment of the present disclosure.DETAILED DESCRIPTION

[0020] The following detailed description of example embodiments refers to the accompanying drawings. The present disclosure provides illustrations and descriptions, but is not intended to beexhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the present disclosure or may be acquired from practice of the implementations. Further, one or more features or components of one embodiment may be incorporated into or combined with another embodiment (or one or more features of another embodiment). Additionally, the flowchart and description of operations provided below relate to at least one of the embodiments in the present disclosure. It should be noted that it is possible to make other embodiments that do not exactly match the flowchart and its description. It is understood that in other embodiments one or more operations may be omitted, one or more operations may be added, one or more operations may be performed simultaneously (at least in part).

[0021] It will be apparent that systems and / or methods, described herein, may be implemented in different forms of hardware, software, or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and / or methods should not limit their implementations. Thus, the operation and behavior of the systems and / or methods are described herein without reference to specific software code. It is understood that software and hardware may be designed to implement the systems and / or methods based on the description herein.

[0022] Even though particular combinations of features are recited in the claims and / or disclosed in the specification, the particular combinations are not intended to limit the disclosure of implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and / or disclosed in the specification. Even if a dependent claim directly depends ononly one claim, the present disclosure may indicate that the dependent claim is dependent on other claims in the claim set.

[0023] No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” (in other words, nouns not mentioned in the plural) are intended to include one or more items, and may be used interchangeably with “one or more.” Also, as used herein, the terms “has,” “have,” “having,” “include,” “including,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Furthermore, expressions such as “at least one of [A] and [B],” “[A] and / or [B],” or “at least one of [A] or [B]” are to be understood as including only A, only B, or both A and B.

[0024] The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the implementations.

[0025] FIG. 1 illustrates an example of a wireless communication network 100, according to related art. The wireless communication network 100 may include one or more UEs 101, a core network 103, and one or more base stations 105. In some examples, the wireless communication network 100 may be a Long Term Evolution (LTE) network, an LTE- Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communication network 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low latency communications, communications with low- cost and low-complexity devices, or any combination thereof.

[0026] The one or more base stations 105a, 105b may be dispersed throughout a geographic area to form the wireless communication network 100 and may be devices in different forms or having different capabilities. The one or more base stations 105a, 105b and the one or more UEs 101a, 101b may wirelessly communicate via one or more communication links 107. Each base station 105a, 105b may provide a coverage area over which the one or more UEs 101a, 101b and the base station 105a, 105b may establish one or more communication links 107. The coverage area may be an example of a geographic area over which one of the base stations 105a, 105b and one of the UEs 101a, 101b may support the communication of signals according to one or more radio access technologies.

[0027] The one or more UEs 101a, 101b may be dispersed throughout the coverage area of the wireless communication network 100, and each UE 101a, 101b may be stationary, mobile, or both at different times. The one or more UEs 101a, 101b may be devices in different forms or having different capabilities.

[0028] One or more of the base stations 105a, 105b described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or a gNodeB (either of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or other suitable terminology.

[0029] The one or more UEs 101a, 101b may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. The one or more UEs 101a, 101b may also include or may be referred toas a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, the one or more UEs 101a, 101b may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (loT) device, an Internet of Everything (loE) device, or a machine-type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, vehicles, meters, among other examples.

[0030] The one or more UEs 101a, 101b described herein may be able to communicate with various types of devices, such as other UEs 101a, 101b that may sometimes act as relays as well as the base stations 105a, 105b and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1. Further, it should be noted that although only two UEs 101a, 101b and two base stations 105a, 105b are depicted in FIG.1 for illustration purposes, the wireless communication network 100 may include additional UEs and base stations not shown in FIG. 1.

[0031] As illustrated in FIG. 1, one or more UEs 101a, and 101b are connected to the base station 105a, such as an eNodeB (eNB). However, if the eNB 105a experiences a failure or goes down, all connected UEs 101a, and 101b will be disconnected. This forces them to perform the RACH and attach procedures again to reconnect to the eNB 105a, which takes time due to the loss of UE context when the eNB fails. This situation can significantly impact critical services or the connected UEs 101a, and 101b.

[0032] In non-standalone (NSA) operation, 4G cells are part of the MCG, while NR cells are part of the SCG. For instance, when UE 101a is operating in E-UTRANNew Radio - Dual Connectivity(EN-DC) mode, the base station 105a corresponds to the MCG cell, and the base station 105bcorresponds to the SCG cell. In this scenario, if the SCG cell 105b fails, the UE 101a can continue its operation over the MCG cell 105a.

[0033] However, if the MCG cell 105a fails, MCGFailurelnformation can help enable fast recovery as specified by the 3rd Generation Partnership Project (3GPP) in specification 36.331, section 5.6.26. According to this specification, split Signaling Radio Bearer (SRB) 1 / 2 or SRB 3 can be used to transmit a UE message regarding the MCG failure cause and related measurements to the SCG cell 105b. The SCG cell 105b can then relay this information to the Mobility Management Entity (MME) for recovery decisions. Nonetheless, if the entire eNB 105a restarts or fails entirely, all UEs 101a, 101b attached to it will go down due to the complete loss of UE context.

[0034] Referring now to the drawings, and more particularly to FIGS. 2 to 9, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

[0035] FIG. 2 illustrates a general Open Radio Access Network (0-RAN) architecture 200 associated with Radio Access Network (RAN) Intelligent Controller (RIC), according to an embodiment of the present disclosure. The O-RAN Alliance, which is a global community of mobile network operators, vendors, and research and academic institutions focused on open RAN standards and interoperability, has defined a set of use cases and applications that the RIC supports. The RIC is divided into non-real-time and near-real-time components. The Non-Real Time RAN Intelligent Controller (Non-RT-RIC) 203 is an element of operator’s centralized Service Management and Orchestration (SMO) 201 Framework, as defined by the 0-RAN Alliance. On the other hand, the near-RT RIC 205 resides within a telco edge or regional cloud and generally enables network optimization actions that take between ten milliseconds to one second to complete.

[0036] The non-RT RIC 203 acts as a control point of a non-real-time control loop and operates on a timescale greater than 1 second within the SMO 201 framework. The functionalities of the non-RT RIC 203 may be implemented through applications called rApps 203a. The non-RT RIC may be connected to a near-RT RIC 205 over an Al interface. The near-RT RIC 205 operates on a timescale between 10 milliseconds and 1 second. The functionalities of the near-RT RIC 205 may be implemented through applications called xApps 205a.

[0037] The near-RT RIC 205 may further be connected to E2 nodes (for instance, enB, gNB) over an E2 interface. The SMO framework 201 may manage and orchestrate various RAN elements. For instance, the SMO 201 may orchestrate an O-RAN Cloud (O-Cloud). The O-Cloud may refer to a collection of physical RAN nodes that host the RICs, O-Centralized Units (CUs), O- Distributed Units (DUs), etc., along with the supporting environments and components.

[0038] In an embodiment, the techniques of the present disclosure have been implemented in the near-RT RIC 205 and are further explained in reference to FIGS. 3-9.

[0039] FIG. 3 illustrates a schematic block diagram of the near-RT RIC 205 for maintaining connection between a UE and a communication node in MRDC mode, according to an embodiment of the present disclosure. The near-RT RIC 205 may include an apparatus 300 configured to perform operation of the near-RT RIC 205. Accordingly, the apparatus 300 may be associated with the near RT-RIC 205 and include at least one xApp 205a. In one embodiment, the apparatus 300 may be implemented within the near RT-RIC 205.

[0040] The apparatus 300 may be configured to receive, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes. In one non-limiting embodiment, theplurality of communication nodes may refer to eNBs 302 and gNBs 304. The plurality of communication nodes may form a plurality of clusters, where each cluster may include one or more of the communication nodes among the plurality of communication nodes. Accordingly, each cluster may serve one or more UEs. For example, the cluster of nodes 302 may serve the one or more UEs 301a, and 301b. Similarly, the cluster of nodes 304 may serve the one or more UEs 303a, and 303b. Accordingly, the apparatus 300 may receive the initial context setup information associated with the one or more UEs 301a, 301b, or 303a, 303b. The apparatus 300 may further be configured to receive, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE, such as 301a from among the one or more UEs. The SCG communication node and the MCG communication node may be among the plurality of communication nodes. For example, the MCG communication node may be among the cluster of nodes 302, and the SCG communication node may be among the cluster of nodes 304. The one or more neighboring cells may be connected to the SCG communication node. The apparatus 300 may be configured to select a cell candidate from among the one or more neighboring cells for the UE 301a in response to receipt of the information associated with one or more neighboring cells. The apparatus 300 may then be configured to transmit the initial context setup information associated with the UE 301a to a target communication node associated with the selected cell candidate. The apparatus 300 may transmit the initial context setup information to trigger a handover for the UE 301a. In a nonlimited embodiment, the target communication node may be among the cluster of nodes 304.

[0041] The apparatus 300 may include one or more processors 308 (hereinafter referred to as the processor 308), a memory 306, and one or more modules 310. In one embodiment, the processor308 may include at least one data processor for executing processes in Virtual Storage AreaNetwork. The processor 308 may include specialized processing units such as integrated system(bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. In one embodiment, the processor 308 may include a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), or both. The processor 308 may be one or more general processors, Digital Signal Processors (DSPs), application-specific integrated circuits, Field-Programmable Gate Arrays (FPGAs), servers, networks, digital circuits, analog circuits, combinations thereof, or other now known or later developed devices for analyzing and processing data. The processor 308 may execute a software program, such as code generated manually (i.e., programmed) to perform the desired operation. The processor 308 may implement various techniques such as, but not limited to, image processing, data extraction, Artificial Intelligence (Al), Machine Learning (ML), Deep Learning (DL), and so forth to achieve the desired objective.

[0042] In one embodiment, the processor 308 may be configured to perform the functions of the apparatus 300.

[0043] The memory 306 may be communicatively coupled to the processor 308. The memory 306 may be configured to store data and instructions executable by the processor 308. In one embodiment, the memory 306 may communicate via a bus within the apparatus 300. The memory 306 may include, but is not limited to, a non-transitory computer-readable storage media, such as various types of volatile and non-volatile storage media including, but not limited to, random access memory, read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, flash memory, magnetic tape or disk,optical media and the like. In one example, the memory 306 may include a cache or random-access memory for the processor 308. In alternative examples, the memory 306 is separate from the processor 308, such as a cache memory of a processor, the system memory, or other memory. The memory 306 may be an external storage device or database for storing data. The memory 306 may be operable to store instructions executable by the processor 308. The functions, acts or tasks illustrated in the figures or described may be performed by the programmed processor 308 for executing the instructions stored in the memory 306. The functions, acts or tasks are independent of the particular type of instructions set, storage media, processor, or processing strategy and may be performed by software, hardware, integrated circuits, firmware, micro-code, and the like, operating alone or in combination. Likewise, processing strategies may include multiprocessing, multitasking, parallel processing, and the like. The memory 306 may further include a database to store the data. Further, the memory 306 may include an operating system for performing one or more tasks of the apparatus 300, as performed by a generic operating system in the communications domain.

[0044] The modules 310, amongst other things, include routines, programs, objects, components, data structures, etc., which perform particular tasks or implement data types. The modules 310 may also be implemented as, signal processor(s), state machine(s), logic circuitries, and / or any other device or component that manipulates signals based on operational instructions. The modules 310 may be configured to one or more operations of the apparatus 300 and / or the processor 308.

[0045] Further, the modules 310 can be implemented in hardware, instructions executed by a processing unit, or by a combination thereof. The processing unit can comprise a computer, the processor 308, a state machine, a logic array, or any other suitable devices capable of processinginstructions. The processing unit can be a general -purpose processor which executes instructions to cause the general-purpose processor to perform the required tasks, or the processing unit can be dedicated to performing the required functions. In another embodiment of the present disclosure, the modules 310 may be machine-readable instructions (software) which, when executed by a processor / processing unit, perform any of the described functionalities. Furthermore, the data serves, amongst other things, as a repository for storing data processed, received, and generated by one or more of the modules. The modules 310 may include a transmitting module 208, a receiving module 212, and a determination module 214.

[0046] The apparatus 300 may also include at least one xAPP 205a for storing the received initial context setup information.

[0047] Detailed explanation of the various functions and the operations of the apparatus 300 and / or the associated processor 308 or the modules 310 has been explained in the following description with reference to FIGS. 4-9.

[0048] FIG. 4 illustrates a schematic operational flow diagram of the plurality of modules 310 of the apparatus 300, in accordance with an embodiment of the present disclosure. The modules 310 may include a receiving module 402, a transmitting module 404, and a selecting module 406. The plurality of modules 310 may be coupled to the at least one xAPP 205a.

[0049] The receiving module 402 may be configured to receive the initial context setup information associated with one or more user equipment (UEs) 301a, 301b, 303a, and 303b, served by a cluster of the plurality of the communication nodes, i.e., MCG and SCG nodes 302, 304. In a non-limited embodiment, the initial context setup information may include information associated with at least one cell serving the one or more UEs, i.e., at least one serving cell. The initial contextsetup information may include, but not limited to, initial context setup request containing UE's security context, Quality of Service (QoS) parameters, Protocol Data Unit (PDU) session contexts and cell details associated with the at least one serving cell. In a non-limited embodiment, FIG. 5 illustrates a signal flow diagram 500 of reception of the initial context setup information, according to an embodiment of the present disclosure. As shown in FIG. 5, at operation 501, a mobility management entity (MME) 502 associated with the UE 301a may receive an initial setup context request from a communication node 502. In response, at operation 503, the MME 504 may transmit an initial context setup response to the communication node 502. Thereafter, at operation 505, the receiving module 402 may receive the initial context setup information from the communication node 502. The initial context setup information may be stored in the xAPP 205a. In another embodiment, the xAPP 205a may also receive the initial context setup information from the communication node 502. It should be noted that although only one communication node 502 is depicted in FIG. 5 for simplicity of representation, the initial context setup information can be received from a plurality of communication nodes (not shown) in a similar manner as illustrated. In a non-limited embodiment, the initial context setup information may be received from the plurality of communication nodes via E2 interface.

[0050] Further, if any modification / update is required in the initial context setup information, then the xAPP may receive the same from the communication node 502. For example, at operation 507, the MME 504 may receive an updated context setup request from the communication node 502. The updated context setup request may include the modification / update to be done in the context. In response, at operation 509, the MME 504 may transmit the updated context setup response to the communication node 502. The communication node 502 may then, at operation 511, transmitthe updated context setup information to the receiving module 402 / xAPP 205a. Accordingly, the xAPP may then modify the context stored therein.

[0051] In a further embodiment, the receiving module 402 may receive, from a SCG communication node 504, information associated with one or more neighboring cells upon failure of a MCG radio link for a UE 301a from among the one or more UEs 301a, 301b. In a non-limited embodiment, the receiving module 402 may receive such information from the SCG communication node 504 as illustrated in FIG. 6. FIG. 6 illustrates a signal flow diagram 600 of reception of information associated with neighboring cells, according to an embodiment of the present disclosure. As shown, at operation 601, the SCG communication node 504 may transmit a failure information of the MCG radio link, i.e., MCGFailurelnformation to a communication node associated with a current MCG, i.e., MCG node 502. The MCG communication node 502 may belong to the cluster of nodes 302 and the SCG communication node 504 may belong to the cluster of nodes 304. The MCG radio link may refer to a radio link between the UE 301a and the MCG node 302. Then, at operation 603, the SCG node 504 starts a timer. At operation 605, the SCG node 504 determines that an acknowledgement message from the currently serving communication node, i.e., MCG 502 has not been received within a predefined duration associated with the timer. Accordingly, at operation 607, the timer stops upon expiry of the predefined duration. It should be noted that the predefined duration and the timer may be configured by the SCG node 504. Then, at operation 609, the receiving module 402 may receive information associated with the one or more neighboring cells upon determination that the acknowledgement from the MCG node 502 has not been received. The information can then be stored in the xAPP 205a. In another embodiment, the xAPP 205a may receive the information associated with the one or moreneighboring cells directly from the SCG node 504. In an embodiment, the information associated with the one or more neighboring cells may be received in the MCGFailurelnformation over the E2 interface.

[0052] The selecting module 406 may select a cell candidate from among the one or more neighboring cells for the UE 301a based on the information associated with the one or more neighboring cells. In an embodiment, the selecting module 406 may select the cell candidate in accordance with techniques known to a person skilled in the art.

[0053] The transmitting module 404 may transmit to a target communication node, the initial context setup information associated with the UE 301a to trigger a handover for the UE 301a. The target communication node may be associated with the selected cell candidate. Accordingly, the target communication node may belong to the cluster of nodes 304. In a non-limited embodiment, the transmitting module 404 may transmit the initial context setup information as illustrated in FIG. 7. FIG. 7 illustrates a signal flow diagram 700 of transmission of the initial context setup information to a target communication node, according to an embodiment of the present disclosure. As shown, at operation 701a, the transmitting module 404 may transmit the initial context setup information to the target communication node 702 (referred to as target node 702). In an embodiment, the xAPP 205a may directly transmit the initial context setup information to the target communication node 702. Accordingly, at operation 703, the target communication node 702 may transmit a handover request to the MME 502 to perform handover using the initial context setup information. In an embodiment, the target communication node 702 may transmit the handover request in a HANDOVER REQUIRED massage for SI handover (HO) with a specific cause. Further, the target communication node 702 may transmit a SI Application Protocol (SI AP)handover required massage to ENB with all the info needed. In a non-limited embodiment, the xAPP 205a may transmit the HANDOVER REQUIRED message to the target communication node 702. Further, the info may include, but not limited to, HO required message, cause, target ID, Source to Target Transparent Container, E-UTRAN Radio Access Bearer (E-RABs) to be Setup List, MME UE SI AP ID, and eNB UE S1AP ID. The Source to Target Transparent Container may include UE Context Information and Security Information. Further, the transmitting module 404 / xAPP 205a may transmit the initial context setup information to the target communication node 702 via the E2 interface. Simultaneously, at step 701b, transmitting module 404 / xAPP 205a may also transmit a radio resource control (RRC) connection reconfiguration request message towards UE 301. The RRC connection reconfiguration request message may be transmitted using one of signaling radio bearer 1 (SRB1) or SRB3 via the SCG communication node 604. In a nonlimited embodiment, the target communication node 702 may be designated as an MCG communication node for the UE 301a in response to triggering the handover for the UE 301a. In particular, now the target communication node 702 is the MCG node for the UE 301a. This way, there is no delay in performing the handover even if the entire MCG node is down. Further, as the UE 301a is connected to the target communication node 702 using the initial context setup information, the information associated with the UE 301a is not lost.

[0054] In a further embodiment, the receiving module 402 / xAPP 205a may receive from the target communication node 702, a context release request message after initiation of handover for the UE 301a at the target communication node 702. In response, the xAPP 205a may delete the initial UE context setup information for the UE 301a. Further, the receiving module 402 / xAPP 205a may also receive the context release request message for normal and abnormal release UE. In a non-limited embodiment, the normal release may occur when the connection between the UE 301a and the MCG communication node 504 is terminated in an orderly manner. However, the abnormal release may occur when the connection between the UE 301a and the MCG communication node 504 is terminated unexpectedly due to issues such as radio link failure, handover failure, or network congestion, etc. Accordingly, the xAPP 205a may delete the corresponding UE context.

[0055] In a non-limited embodiment, the functions of various module 310 may be performed by the xAPP 205a. In a further embodiment, when the wireless communication network 100 is a 5G network and the MCG corresponds to gNB (i.e., LTE), then the MCG may communicate with 5G core (5GC) using an N26 interface.

[0056] FIG. 8 illustrates a flowchart depicting a method 800 for maintaining connection between the UE and the communication node in MRDC mode, according to an embodiment of the present disclosure. The method 800 may be performed by the apparatus 300.

[0057] At step 801, the method 800 may include receiving, by the apparatus 300, from a plurality of communication nodes, an initial context setup information associated with one or more UEs served by a cluster of the plurality of the communication nodes. The initial context setup information may include information associated with at least one cell serving the one or more UEs and is received from the plurality of communication nodes via E2 interface. Further, in a nonlimited embodiment, the MME associated with the UE may receive an initial context setup response message from the corresponding communication node. In response, the corresponding communication node may receive the initial context setup information in response to the initial context setup response message. Then, initial context setup information may be received from the communication node.

[0058] At step 803, the method 800 may include receiving, by the apparatus 300, from a SCG communication node, information associated with one or more neighboring cells upon failure of aMCG radio link for the UE 301a from among the one or more UEs. In a non-limited embodiment, the information associated with one or more neighboring cells may be received when the SCG communication node fails to receive an acknowledgement message from the currently serving communication node within a predefined duration associated with a timer.

[0059] At step 805, the method 800 may include in response to receipt of the information associated with one or more neighboring cells, selecting, by the apparatus 300, a cell candidate from among the one or more neighboring cells for the UE.

[0060] At step 807, the method 800 may include transmitting, by the apparatus 300, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE. In a non-limited embodiment, the initial context setup information may be transmitted to the target communication node via the E2 interface.

[0061] While the above-discussed steps in FIG. 8 are shown and described in a particular sequence, the steps may occur in variations to the sequence in accordance with various embodiments. Further, a detailed description related to the various steps of FIG. 8 is already covered in the description related to FIGS. 2-7 and is omitted herein for the sake of brevity.

[0062] FIG. 9 is a diagram of example components of a wireless communication device 900 (also referred to as the device / apparatus 900), in accordance with an embodiment of the present disclosure. In one or more embodiments, the wireless communication device 900 may correspond to a wireless server and / or the apparatus 300. As shown in FIG. 9, the device 900 includes aprocessor 910, a memory 920, a storage component 930, an input component 940, an output component 950, a communication interface 960, and a bus 970.

[0063] The processor 910, as used herein, means any type of computational circuit that may comprise hardware elements and software elements. The processor 910 may be embodied as a multi-core processor, a single-core processor, or a combination of one or more multi-core processors and / or one or more single-core processors, a distributed processing system, or the like. The processor 910 may be a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), an Accelerated Processing Unit (APU), an Application-Specific Integrated Circuit (ASIC), or another type of processing component.

[0064] The memory 920 includes a non-transitory computer-readable medium. The memory 920 includes a Random-Access Memory (RAM), a Read Only Memory (ROM), and / or another type of dynamic or static storage device (e.g., a flash memory, a magnetic memory, and / or an optical memory) that stores information and / or instructions for use by the processor 910. The memory 920 comprises machine-readable instructions which are executable by the processor 910. These machine-readable instructions when executed by the processor 910 cause the processor 910 to perform one or more method steps of an embodiment described above.

[0065] The storage component 930 stores information and / or software related to the operation and use of the device 900. For example, the storage component 930 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, and / or a solid-state disk), a Compact Disc (CD), a Digital Versatile Disc (DVD), a floppy disk, a cartridge, a magnetic tape, and / or another type of non-transitory computer-readable medium, along with a corresponding drive.

[0066] The input component 940 is configured to receive information, such as user input. For example, the input component 940 may include, but not be limited to, a touch screen display, a keyboard, a keypad, a mouse, a button, a switch, and / or a microphone. Additionally, or alternatively, the input component 940 may include a sensor for sensing information (e.g., a Global Positioning System (GPS), an accelerometer, a gyroscope, and / or an actuator).

[0067] The output component 950 is configured to provide output information from the device 900. For example, the output component 950 may include, but is not limited to, a display, a speaker, an instruction device to an external device, and / or one or more Light-Emitting Diodes (LEDs).

[0068] The communication interface 960 is an interface that provides a communication connection to other devices, such as external devices and internal devices. The connection by the communication interface 960 can be a wired connection, a wireless connection, or a combination of wired and wireless connections, and can be a direct connection or an indirect connection via a communication network that exists between the device 900 and other devices. In other words, the standard of the communication interface 960 is not limited.

[0069] The bus 970 acts as an interconnect between the processor 910, the memory 920, the storage component 930, the input component 940, the output component 950, and the communication interface 960 of the device 900. The bus 970 may include a wired interconnection or a wireless interconnection.

[0070] The number and arrangement of components shown in FIG. 9 are provided as an example. In practice, the device 900 may include additional components, fewer components, different components, or differently arranged components than those shown in FIG. 9. Additionally, or alternatively, a set of components (e.g., one or more components) of the device 900 may performone or more functions described as being performed by another set of components of the device 900. Further, one or more method steps described in any of the embodiments may be performed utilizing a plurality of devices 900 in communication with one another.

[0071] It is understood that terms including “unit” or “module” at the end may refer to the unit for processing at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software.

[0072] In one embodiment, a method is described. The method includes receiving, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes. Further, the method includes receiving, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs. The method further includes in response to receipt of the information associated with one or more neighboring cells, selecting a cell candidate from among the one or more neighboring cells for the UE. The method also includes transmitting, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

[0073] The method as described in

[0071] , the method comprises: transmitting radio resource control (RRC) connection reconfiguration request message towards UE, using one of signaling radio bearer 1 (SRB1) or SRB3 via the SCG communication node

[0074] The method as described in any one of

[0071] -

[0072] , the method comprises: receiving, from the plurality of communication nodes, an updated context setup information associated with the one or more user equipment (UEs); andmodifying the initial context information with the updated context setup information prior to the transmission to the target communication node.

[0075] The method as described in any one of

[0071] -

[0073] , the method comprises: receiving, from the target communication node, a context release request message after initiation of handover for the UE at the target communication node; and deleting the initial UE context setup information for the UE in response to receipt of the context release request message.

[0076] The method as described in any one of

[0071] -

[0074] , wherein the transmitting comprises transmitting the initial context setup information associated with the UE to designate the target communication node as an MCG communication node for the UE in response to triggering the handover for the UE.

[0077] The method as described in any one of

[0071] -

[0075] , wherein receiving, from the secondary cell group (SCG) communication node, comprises: receiving information associated with one or more neighboring cells, when the SCG communication node fails to receive, in response to transmission of failure information of the MCG radio link to a communication node associated with a current MCG, an acknowledgement message from the currently serving communication node within a predefined duration associated with a timer.

[0078] The method as described in any one of

[0071] -

[0076] , wherein receiving, from each of the plurality of communication nodes, comprises: receiving the initial context setup information associated with the one or more user equipment (UEs) in response to transmission of an initial context setup response message by thecorresponding communication node towards a mobility management entity (MME) associated with the UE after the receipt of the initial context setup information by the corresponding communication node from the MME.

[0079] The method as described in any one of

[0071] -

[0077] , wherein the initial context setup information comprises information associated with at least one cell serving the one or more UEs, wherein receiving initial context setup information comprises receiving the initial context setup request from the plurality of eNBs via E2 interface, and wherein the transmitting comprises transmitting the initial context setup information to the target eNB via E2 interface.

[0080] In another embodiment, an apparatus is described. The apparatus is configured to receive, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes. The apparatus is further configured to receive, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs. The apparatus is also configured to, in response to receipt of the information associated with one or more neighboring cells, select a cell candidate from among the one or more neighboring cells for the UE. The apparatus is further configured to transmit, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

[0081] The apparatus as described in

[0079] , wherein the apparatus is further configured to transmit radio resource control (RRC) connection reconfiguration request message towards UE using one of signaling radio bearer 1 (SRB1) or SRB3 via the SCG communication node.

[0082] The apparatus as described in any one of

[0079] -

[0080] , wherein the apparatus is further configured to: receive, from the plurality of communication nodes, an updated context setup information associated with the one or more user equipment (UEs); and modify the initial context information with the updated context setup information prior to the transmission to the target communication node

[0083] The apparatus as described in any one of

[0079] -

[0081] , wherein the apparatus is further configured to: receive, from the target communication node, a context release request message after initiation of handover for the UE at the target communication node; and delete the initial UE context setup information for the UE in response to receipt of the context release request message.

[0084] The apparatus as described in any one of

[0079] -

[0082] , wherein to transmit, the apparatus is configured to transmit the initial context setup information associated with the UE to designate the target communication node as an MCG communication node for the UE in response to triggering the handover for the UE.

[0085] The apparatus as described in any one of

[0079] -

[0083] , wherein the apparatus is configured to receive, from the secondary cell group (SCG) communication node, information associated with one or more neighboring cells, when the SCG communication node fails to receive, in response to transmission of failure information of the MCG radio link to a communication node associated with a current MCG, an acknowledgement message from the currently serving communication node within a predefined duration associated with a timer.

[0086] The apparatus as described in any one of

[0079] -

[0084] , wherein the apparatus is configured to receive, from each of the plurality of communication nodes, the initial context setup information associated with the one or more user equipment (UEs) in response to transmission of an initial context setup response message by the corresponding communication node towards a mobility management entity (MME) associated with the UE after the receipt of the initial context setup information by the corresponding communication node from the MME.

[0087] The apparatus as described in any one of

[0079] -

[0085] , wherein the apparatus is configured to receive the initial context setup request from the plurality of communication nodes via E2 interface.

[0088] The apparatus as described in any one of

[0079] -

[0086] , wherein the apparatus is configured to transmit the initial context setup information to the target communication node via E2 interface.

[0089] The apparatus as described in any one of

[0079] -

[0087] , wherein the initial context setup information comprises information associated with at least one cell serving the one or more UEs.

[0090] The apparatus as described in any one of

[0079] -

[0088] , wherein the apparatus is associated with a Near-Real Time Radio Access Network Intelligent Controller (near RT-RIC) comprising at least one extended application (xApp), and wherein the xApp is configured to store the received initial context setup information.

[0091] In one embodiment, a non-transitory computer-readable medium storing instructions is described. The non-transitory computer-readable medium storing instructions, the instructions comprising: one or more instructions that, when executed by an apparatus, the apparatus comprising one or more processors, cause the one or more processors to receive, from a pluralityof communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes. The one or more instructions further cause the one or more processor to receive, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs. The one or more instructions further cause the one or more processor to, in response to receipt of the information associated with one or more neighboring cells, select a cell candidate from among the one or more neighboring cells for the UE. The one or more instructions further cause the one or more processor to transmit, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

[0092] Accordingly, the present disclosure provides techniques for reducing the outage UE connected with MRDC by saving the UE context in xAPP.

[0093] Embodiments of the present disclosure offers several significant commercial and technical advantages, for example:

[0094] Faster handover in MRDC: allowing the UE to perform a faster handover by saving the UE context in the xAPP.

[0095] Securing connection in case of eNB failure: In case of eNB failure, the connection between the UE and the network is secured using the UE context stored in the xAPP.

[0096] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.

[0097] The drawings and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein.

[0098] Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims.

[0099] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any component(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or component of any or all the claims.

[0100] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is tobe understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of at least one embodiment, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Claims

We Claim:

1. An apparatus configured to: receive, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes; receive, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs; in response to receipt of the information associated with one or more neighboring cells, select a cell candidate from among the one or more neighboring cells for the UE; and transmit, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

2. The apparatus of claim 1, wherein the apparatus is further configured to: transmit radio resource control (RRC) connection reconfiguration request message towards UE using one of signaling radio bearer 1 (SRB1) or SRB3 via the SCG communication node.

3. The apparatus of claim 1, wherein the apparatus is further configured to:receive, from the plurality of communication nodes, an updated context setup information associated with the one or more user equipment (UEs); and modify the initial context information with the updated context setup information prior to the transmission to the target communication node.

4. The apparatus of claim 1, wherein the apparatus is further configured to: receive, from the target communication node, a context release request message after initiation of handover for the UE at the target communication node; and delete the initial UE context setup information for the UE in response to receipt of the context release request message.

5. The apparatus of claim 1, wherein to transmit, the apparatus is configured to transmit the initial context setup information associated with the UE to designate the target communication node as an MCG communication node for the UE in response to triggering the handover for the UE.

6. The apparatus of claim 1, wherein the apparatus is configured to receive, from the secondary cell group (SCG) communication node, information associated with one or more neighboring cells, when the SCG communication node fails to receive, in response to transmission of failure information of the MCG radio link to a communication nodeassociated with a current MCG, an acknowledgement message from the currently serving communication node within a predefined duration associated with a timer.

7. The apparatus of claim 1, wherein the apparatus is configured to receive, from each of the plurality of communication nodes, the initial context setup information associated with the one or more user equipment (UEs) in response to transmission of an initial context setup response message by the corresponding communication node towards a mobility management entity (MME) associated with the UE after the receipt of the initial context setup information by the corresponding communication node from the MME.

8. The apparatus of claim 1, wherein the apparatus is configured to receive the initial context setup request from the plurality of communication nodes via E2 interface.

9. The apparatus of claim 1, wherein the apparatus is configured to transmit the initial context setup information to the target communication node via E2 interface.

10. The apparatus of claim 1, wherein the initial context setup information comprises information associated with at least one cell serving the one or more UEs.

11. The apparatus of claim 1, wherein the apparatus is associated with a Near-Real Time Radio Access Network Intelligent Controller (near RT-RIC) comprising at least one extendedapplication (xApp), and wherein the xApp is configured to store the received initial context setup information.

12. A method comprising: receiving, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes; receiving, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs; in response to receipt of the information associated with one or more neighboring cells, selecting a cell candidate from among the one or more neighboring cells for the UE; and transmitting, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

13. The method of claim 12 further comprising: transmitting radio resource control (RRC) connection reconfiguration request message towards UE, using one of signaling radio bearer 1 (SRB1) or SRB3 via the SCG communication node.

14. The method of claim 12 further comprising: receiving, from the plurality of communication nodes, an updated context setup information associated with the one or more user equipment (UEs); and modifying the initial context information with the updated context setup information prior to the transmission to the target communication node.

15. The method of claim 12 further comprising: receiving, from the target communication node, a context release request message after initiation of handover for the UE at the target communication node; and deleting the initial UE context setup information for the UE in response to receipt of the context release request message.

16. The method of claim 12, wherein the transmitting comprises transmitting the initial context setup information associated with the UE to designate the target communication node as an MCG communication node for the UE in response to triggering the handover for the UE.

17. The method of claim 12, wherein receiving, from the secondary cell group (SCG) communication node, comprises: receiving information associated with one or more neighboring cells, when the SCG communication node fails to receive, in response to transmission of failure information of the MCG radio link to a communication node associated with a current MCG, anacknowledgement message from the currently serving communication node within a predefined duration associated with a timer.

18. The method of claim 12, wherein receiving, from each of the plurality of communication nodes, comprises: receiving the initial context setup information associated with the one or more user equipment (UEs) in response to transmission of an initial context setup response message by the corresponding communication node towards a mobility management entity (MME) associated with the UE after the receipt of the initial context setup information by the corresponding communication node from the MME.

19. The method of claim 12, wherein the initial context setup information comprises information associated with at least one cell serving the one or more UEs, wherein receiving initial context setup information comprises receiving the initial context setup request from the plurality of eNBs via E2 interface, and wherein the transmitting comprises transmitting the initial context setup information to the target eNB via E2 interface.

20. A non-transitory computer-readable medium storing instructions, the instructions comprising:one or more instructions that, when executed by an apparatus comprising one or more processors, cause the one or more processors to: receive, from a plurality of communication nodes, an initial context setup information associated with one or more user equipment (UEs) served by a cluster of the plurality of the communication nodes; receive, from a secondary cell group (SCG) communication node, information associated with one or more neighboring cells upon failure of a master cell group (MCG) radio link for a UE from among the one or more UEs; in response to receipt of the information associated with one or more neighboring cells, select a cell candidate from among the one or more neighboring cells for the UE; and transmit, to a target communication node associated with the selected cell candidate, the initial context setup information associated with the UE to trigger a handover for the UE.

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