Detecting Physical Cell Identifier (PCI) Confusion During Secondary Node (SN) Change Procedure in Wireless Networks

Abstract

An embodiment of the present disclosure discloses a first secondary node element (203-1) for detecting physical cell identifier (PCI) confusion during a secondary node (SN) change procedure. The first secondary node element (203-1) receives secondary cell group (SCG) failure information from a UE (201) during handover from the first secondary node element (203-1) to a second secondary node element (203-2), indicating that the cause of the handover failure is a random access channel failure. The first secondary node element (203-1) recognizes, based on the cause, that the failure is due to PCI confusion related to the PCI of the second secondary node element (203-2) within a predetermined period of a timer configured in a primary node element (202) for maintaining the UE (201) context in the first secondary node element (203-1). The first secondary node element (203-1) performs a mitigation action during a subsequent handover from a secondary node element to a secondary node element for a UE in the wireless network when the PCI of one of the secondary node elements is the same as the recognized PCI.

Description

[Technical Field]

[0001] The present disclosure relates generally to the field of wireless communication networks, and more particularly to detecting Physical Cell Identifier (PCI) confusion during Secondary Node (SN) change procedures in wireless networks. [Background technology]

[0002] Wireless communication networks, such as fifth-generation (5G) networks, have a wide range of applications and services due to their various advantages, such as faster speeds and reduced latency. 5G networks are constantly evolving, and new technologies are being implemented to provide improvised 5G networks. One such technology is 5G New Radio Evolved-Universal Terrestrial Radio Access-New Radio (E-UTRAN) Dual Connectivity (5G NR EN-DC). 5G NR EN-DC enables user equipment (UE) to exchange data between itself and a 5G NR base station along with simultaneous connection with a Long Term Evolution (LTE) / fourth generation (4G) base station. Interworking between LTE and 5G NR base stations is established. 5G NR EN-DC enables the UE to leverage the advantages of both technologies, such as higher speeds and increased bandwidth.

[0003] In 5G NR EN-DC, LTE node elements act as anchor / master node elements, and a UE performs initial registration with the master node element. 5G NR node elements act as secondary node elements associated with the master node element and communicate with the UE via the master node element. Thus, the UE is connected to the master node element and the secondary node element to communicate over the network. Generally, it may be necessary to change the secondary node element due to various reasons, such as poor network conditions of the current secondary node element. This is called a secondary node change procedure (SN change procedure), in which a handover from the current secondary node element to another secondary node element in the network is performed. However, various types of failures can occur during the SN change procedure. Therefore, to efficiently facilitate handovers that improve user experience, it is necessary to detect such failures and take necessary actions.

[0004] The information provided in the Background section of this disclosure is intended only to enhance understanding of the general background of the present invention and should not be construed as an admission or any form of suggestion that this information constitutes prior art already known to those skilled in the art. Summary of the Invention

[0005] One embodiment of the present disclosure discloses a first secondary node element. The first secondary node element includes a processor and a memory. The processor is configured to receive secondary cell group (SCG) failure information from a user equipment (UE) via a primary node element during handover of the UE from the first secondary node element to a second secondary node element. The SCG failure information indicates a cause of the handover failure as a random access channel (RACH) failure. The processor is further configured to recognize, based on the cause, that the failure is due to physical cell identifier (PCI) confusion associated with a PCI of the second secondary node element. The processor recognizes that the failure is due to PCI confusion within a predetermined period associated with a timer configured in the primary node element to maintain the UE's context on the first secondary node element. Thereafter, the processor is configured to perform a mitigation action during a subsequent handover for one of the plurality of UEs in the wireless network from the first secondary node element to one of the plurality of secondary node elements when the PCI of the one of the plurality of secondary node elements is the same as the recognized PCI.

[0006] One embodiment of the present disclosure discloses a primary node element. The primary node element includes a processor and a memory. The processor configures a timer to retain a user equipment (UE) context at a first secondary node element for a predetermined period during a handover of the UE from a first secondary node element to a second secondary node element. The processor also receives secondary cell group (SCG) failure information from the UE. The SCG failure information indicates a cause of the handover failure as a random access channel (RACH) failure. The processor also transmits the SCG failure information to the first secondary node element. The first secondary node element recognizes that the failure is due to physical cell identity (PCI) confusion and uses the SCG failure information to perform mitigation actions during a subsequent handover from the first secondary node element to one of the multiple secondary node elements for one of multiple UEs in a wireless network.

[0007] One embodiment of the present disclosure discloses a method. The method includes receiving secondary cell group (SCG) failure information from a user equipment (UE) via a primary node element during a handover of the UE from a first secondary node element to a second secondary node element. The SCG failure information indicates a cause of the handover failure as a random access channel (RACH) failure. The method further includes recognizing, based on the cause, that the failure is due to a physical cell identifier (PCI) confusion associated with a PCI of the second secondary node element. The failure is recognized within a predetermined period associated with a timer configured in the primary node element to retain the UE's context on the first secondary node element. Thereafter, the method includes performing a mitigation action during a subsequent handover from the first secondary node element to one of a plurality of secondary node elements for one of a plurality of UEs in a wireless network when the PCI of one of the plurality of secondary node elements is the same as the recognized PCI.

[0008] One embodiment of the present disclosure discloses a non-transitory computer-readable medium. The non-transitory computer-readable medium includes instructions for performing operations, including receiving secondary cell group (SCG) failure information from a user equipment (UE) via a primary node element during a handover of the UE from a first secondary node element to a second secondary node element. The SCG failure information indicates a cause of the handover failure as a random access channel (RACH) failure. The operations further include recognizing, based on the cause, that the failure is due to a physical cell identifier (PCI) confusion associated with a PCI of the second secondary node element. The failure is recognized within a predetermined period associated with a timer configured in the primary node element to retain the UE's context on the first secondary node element. Thereafter, the operations include performing a mitigation operation during a subsequent handover from the first secondary node element to one of a plurality of secondary node elements for one of a plurality of UEs in a wireless network when the PCI of one of the plurality of secondary node elements is the same as the recognized PCI.

[0009] The foregoing summary of the invention is illustrative only and is not intended to be in any way limiting. In addition to the exemplary aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

[0010] The novel features and characteristics of the present disclosure are set forth in the appended claims. However, the disclosure itself, as well as its preferred modes of use, further objects and advantages, will best be understood by reference to the following detailed description of illustrative embodiments taken in conjunction with the accompanying drawings. One or more embodiments will now be described, by way of example only, with reference to the accompanying drawings in which like reference numerals represent like elements. [Brief explanation of the drawings]

[0011] [Figure 1A]This shows the 5G New Radio Evolved-Universal Terrestrial Radio Access-New Radio (E-UTRAN) Dual connectivity (5G NR EN-DC) architecture.

[0012] [Figure 1B] The conventional procedure for changing a secondary node (SN) is shown below.

[0013] [Figure 2] 1 illustrates an example environment for detecting PCI confusion during a SN change procedure in a wireless network, in accordance with some embodiments of the present disclosure.

[0014] [Figure 3] FIG. 1 illustrates a detailed diagram of a first secondary node element for detecting PCI confusion during an SN change procedure in a wireless network, in accordance with some embodiments of the present disclosure.

[0015] [Figure 4A] FIG. 1 illustrates an example diagram for detecting PCI confusion during an SN change procedure in a wireless network, in accordance with some embodiments of the present disclosure. [Figure 4B] FIG. 1 illustrates an example diagram for detecting PCI confusion during an SN change procedure in a wireless network, in accordance with some embodiments of the present disclosure.

[0016] [Figure 5] 1 illustrates a diagram of a primary node element for detecting PCI confusion during an SN change procedure in a wireless network, in accordance with some embodiments of the present disclosure.

[0017] [Figure 6A] 1 illustrates an exemplary flowchart illustrating method steps for detecting PCI confusion during an SN change procedure in a wireless network, according to some embodiments of the present disclosure.

[0018] [Figure 6B] 1 shows an exemplary diagram for detecting PCI confusion during SN change procedure in a Centralized Unit (CU) network.

[0019] [Figure 7] 1 illustrates a block diagram of a general-purpose computing system for detecting PCI confusion during a SN change procedure in a wireless network, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0020] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flowcharts, flow diagrams, state transition diagrams, pseudocode, and the like represent various processes that may be substantially represented on a computer-readable medium and executed by a computer or processor, whether or not a computer or processor is explicitly depicted.

[0021] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0022] While the present disclosure is susceptible to various modifications, variations, and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but rather, the disclosure is intended to cover all modifications, variations, equivalents, and alternatives falling within the scope of the present disclosure.

[0023] The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion (may include items other than those listed), whereby a setup, device, or method comprising a list of components or steps does not include only those components or steps, but may also include other components or steps not expressly listed or inherent in such setup or device or method. In other words, "comprising" followed by one or more elements in a system or apparatus does not, without further constraints, exclude the presence of other or additional elements in the system or apparatus.

[0024] FIG. 1A illustrates a 5G New Radio Evolved-Universal Terrestrial Radio Access-New Radio (E-UTRAN) Dual connectivity (5G NR EN-DC) architecture. 5G NR EN-DC enables a user equipment (UE) to exchange data between itself and 5G node elements along with simultaneous connectivity with Long Term Evolution (LTE) node elements. There is interworking between the LTE node elements and the 5G node elements. As shown in FIG. 1A, the 5G NR EN-DC architecture includes an Evolved Packet Core (EPC) or core network (shown as including a Mobility Management Entity (MME) / Serving Gateway (SGW)), multiple Evolved Node Bs (eNBs) or LTE node elements, and multiple NR eNBs (en-gNBs) or 5G node elements. In 5G NR EN-DC, the eNB is also referred to as the master node element. The master node element provides a control plane connection to the core network, i.e., the master node element communicates data and control information with the core network. The en-gNB is called a secondary node element. The secondary node element does not have a control plane connection to the core network. The secondary node element provides additional resources required by the UE. The UE is connected to an eNB functioning as a master node (MN) and an en-gNB functioning as a secondary node (SN). The eNB is connected to the EPC via an S1 interface and to the en-gNB via an X2 interface. The en-gNB is connected to the EPC via an S1-U interface and to other en-gNBs via an X2-U interface.

[0025] Generally, it may be necessary to change the SN connected to a UE due to various reasons, such as poor network conditions of the current SN. The procedure performed for changing from a current SN to another SN in a wireless network is called a Secondary Node (SN) change procedure. A handover from a current SN to another SN in a wireless network is performed. FIG. 1B illustrates a conventional SN change procedure. In FIG. 1B, the current SN is denoted as the Source SN (S-SN), and the other SN to which handover needs to be performed is denoted as the Target SN (T-SN). The conventional SN change procedure can be briefly described as follows: In step 1, the S-SN determines whether an SN change is necessary based on a measurement report received from the UE. In one example, the measurement report may indicate poor network conditions of the S-SN. The S-SN indicates a request for SN change to the MN. The MN initiates the SN change procedure with the T-SN and performs Radio Resource Control (RRC) reconfiguration with the T-SN in steps 2 to 7. Next, the UE performs a random access procedure in step 8, after which the bearer is modified to connect the UE to the T-SN. The UE's context stored in the S-SN is released to complete the handover from the S-SN to the T-SN. The conventional SN change procedure is well known in the art and will not be described in detail.

[0026] During the SN change procedure described above, a handover failure from an S-SN to a T-SN may occur for various reasons. One reason may include new radio physical cell identity confusion (NR-PCI confusion) (also referred to as PCI confusion in this description). PCI confusion occurs when two neighboring cells, either the same en-gNB or different en-gNBs, are associated with the same physical cell identity (PCI). PCI is the identification information of a cell at the physical layer. Due to PCI confusion, a handover may be triggered toward an incorrect en-gNB. For example, there may be one or more en-gNBs with the same PCI as the en-gNB indicated by the UE to perform the handover. This leads to a handover failure. In a conventional SN change procedure, such PCI confusion is not detected. Therefore, the S-SN does not recognize that the failure is due to PCI confusion. Therefore, the S-SN cannot perform any mitigation action to avoid such a failure during future handovers from an S-SN to a T-SN. The present disclosure provides a secondary node element that has the ability to detect that a failure is due to PCI confusion and to perform mitigating actions to avoid such failures during future handovers of the UE in the wireless network.

[0027] FIG. 2 illustrates an example environment 200 for detecting PCI confusion during an SN change procedure in a wireless network, according to an embodiment of the present disclosure. The example environment 200 includes a user equipment (UE) 201, a primary node element 202, and multiple secondary node elements 203-1, 203-2, ..., 203-N (collectively referred to as multiple secondary node elements 203). The UE 201 is configured to connect via a wireless network including the primary node element 202 and the multiple secondary node elements 203. Examples of the UE 201 include, but are not limited to, any device used by a user to communicate and / or access content. Examples of the device include, but are not limited to, a mobile phone, a smartphone, a laptop computer, a wearable device, and an Internet of Things (IoT) device. The UE 201 is connected to the primary node element 202. The primary node element 202 (also referred to as an eNB) may be an LTE or fourth generation (4G) node element. The primary node element 202 provides a control plane connection to the core network, i.e., the primary node element 202 communicates data and control information with the core network. The primary node element 202 is also referred to as a master node element. Furthermore, the UE 201 is connected to one secondary node element among multiple secondary node elements 203. Each of the multiple secondary node elements 203 is a 5G node element. The multiple secondary node elements 203 do not have a control plane connection to the core network. The multiple secondary node elements 203 provide additional resources required by the UE 201. The multiple secondary node elements 203 form a secondary cell group (SCG) in the wireless network. In this disclosure, the secondary node element connected to the UE 201 is referred to as a first secondary node element 203-1. During the SN change procedure, the first secondary node element 203-1 and the UE 201 may communicate with each other via the primary node element 202.

[0028] In the present disclosure, a first secondary node element 203-1 is configured to detect PCI confusion during an SN change procedure in a wireless network. The first secondary node element 203-1 connected to a UE 201 may determine that an SN change is necessary based on a measurement report received from the UE 201. Therefore, the first secondary node element 203-1 may initiate an SN change procedure for handover from the first secondary node element 203-1 to another secondary node element (referred to herein as a second secondary node element 203-2). The first secondary node element 203-1 receives SCG failure information indicating a failure of handover from the first secondary node element 203-1 to the second secondary node element 203-2. In the present disclosure, the SCG failure information indicates the cause of the handover failure as a random access channel (RACH) failure. This helps the first secondary node element 203-1 recognize that the failure may be due to PCI confusion. PCI confusion occurs when two adjacent cells or en-gNBs are associated with the same physical cell identifier (PCI), which is the identity of a cell at the physical layer.

[0029] In the present disclosure, a timer is configured in the primary node element 202. The first secondary node element 203-1 recognizes, within a predetermined period associated with the timer, that the failure is due to a PCI confusion associated with the PCI of the second secondary node element 203-2. The timer ensures that the context of the UE 201 is preserved until the first secondary node element 203-1 recognizes the failure. The first secondary node element 203-1 stores the PCI associated with the PCI confusion, thereby performing mitigation actions during subsequent handovers in the wireless network. Thus, the present disclosure enables the first secondary node element 203-1 to perform mitigation actions during subsequent handovers from the first secondary node element (203-1) to one of the multiple secondary node elements 203 for a UE in a wireless network when the PCI of the one of the multiple secondary node elements 203 is the same as the recognized PCI.

[0030] 3 shows a detailed diagram of a first secondary node element 203-1 for detecting PCI confusion during an SN change procedure in a wireless network, according to some embodiments of the present disclosure. The first secondary node element 203-1 may include an input / output (I / O) interface 301, a memory 302, and a central processing unit (also referred to as a CPU or processor 303). In some embodiments, the memory 302 may be communicatively coupled to the processor 303. The memory 302 stores instructions executable by the processor 303. The processor 303 may comprise at least one data processor for executing program components for executing a request generated by a user or a system. The memory 302 may be communicatively coupled to the processor 303. The memory 302 stores instructions executable by the processor 303, which, when executed, may cause the processor 303 to detect PCI confusion during an SN change procedure in a wireless network. The I / O interface 301 is coupled to a processor 303 that communicates input and / or output signals. For example, SCG failure information may be received from the primary node element 202 via the I / O interface 301. In one embodiment, the first secondary node element 203-1 may be implemented in a variety of computing systems, such as a server, a network server, and a cloud-based server.

[0031] In one embodiment, memory 302 may include one or more modules 305 and data 304. The one or more modules 305 may be configured to perform the steps of the present disclosure using the data 304 to detect PCI confusion during an SN change procedure in a wireless network. In one embodiment, each of the one or more modules 305 may be a hardware unit external to memory 302 and coupled (connected) to first secondary node element 203-1. As used herein, the term module 305 refers to an application specific integrated circuit (ASIC), an electronic circuit, a field-programmable gate array (FPGA), a programmable system-on-chip (PSoC), a combinational logic circuit, and / or other suitable component that provides the described functionality. One or more modules 305, when configured to have the described functionality defined in this disclosure, result in novel hardware.

[0032] In one embodiment, modules 305 may include, for example, input module 310, failure recognition module 311, mitigation module 312, and other module 313. It will be appreciated that such aforementioned modules may be represented as a single module or a combination of different modules. In one embodiment, data 304 may include, for example, input data 306, failure data 307, mitigation data 308, and other data 309.

[0033] In one embodiment, the input module 310 may be configured to receive SCG failure information from the UE 201 via the primary node element 202. The input module 310 may receive the SCG failure information when a handover from a first secondary node element 203-1 to a second secondary node element 203-2 fails. Here, first, one secondary node element among the plurality of secondary node elements 203 may be identified by the UE 201 to perform the handover. The secondary node element may be identified based on one or more network parameters associated with each of the plurality of secondary node elements 203. For example, a secondary node element having the highest signal strength among the plurality of secondary node elements 203 may be identified. The first secondary node element 203-1 may initiate a handover from the first secondary node element 203-1 to the second secondary node element 203-2.

[0034] A random access procedure may be performed by the UE 201 for handover from the first secondary node element 203-1 to the second secondary node element 203-2, which may fail for various reasons. Next, the input module 310 may receive SCG failure information from the UE 201. In the present disclosure, the input module 310 may receive the SCG failure information indicating the cause of the failure as a RACH failure. The RACH failure indicates that the UE is unable to synchronize with the wireless network. Referring to FIG. 4A, an SN change procedure according to an embodiment of the present disclosure is shown. In steps 1 and 2, an SN change is initiated. When a handover from the first secondary node element 203-1 to the second secondary node element 203-2 is performed as shown in steps 3 to 9, a random access failure is notified in step 10. In step 11, the UE 201 transmits SCG failure information to the primary node element 202, indicating the cause of the failure as a RACH failure. In step 12, the input module 310 receives SCG failure information from the primary node element 202. Referring back to FIG. 3, the SCG failure information indicating a RACH failure may be stored in the memory 302 as input data 306. An embodiment of the present disclosure enables the first secondary node element 203-1 to receive the SCG failure along with the cause of the failure as a RACH failure, which helps to detect the failure.

[0035] In one embodiment, the failure recognition module 311 may be configured to receive the input data 306 from the input module 310. Further, the failure recognition module 311 may be configured to recognize that the failure is due to PCI confusion related to the PCI of the second secondary node element 203-1. The failure recognition module 311 may determine that the SCG failure information indicates the cause of the failure as a RACH failure. The cause of the failure as a RACH failure provides the failure recognition module 311 with an indication that the failure is due to PCI confusion. Thus, the failure recognition module 311 may recognize that the failure is due to PCI confusion based on the cause. In one embodiment, the failure recognition module 311 may be configured to recognize that the failure is due to PCI confusion within a predetermined period associated with a timer. The timer may be configured in the primary node element 202 to retain the context of the UE 201. In one embodiment, the timer may be configured when an SgNB reconfiguration process is completed. In a conventional SN change procedure, the UE 201's context is released before the UE 201 completes the random access procedure. The present disclosure enables configuration of a timer in the primary node element 202 to maintain the UE 201's context. The failure recognition module 311 can be configured to recognize a failure within a predetermined period to ensure that the failure is recognized before releasing the UE 201's context. In one example, the predetermined period can be in the range of 100 ms to 5000 ms.

[0036] In one embodiment, the failure recognition module 311 may be configured to record the PCI confusion for the PCI of the second secondary node element 203-2 in a Neighbor Relation Table (NRT) of the first secondary node element 203-1. The NRT maintains a list of neighbor cells with their PCIs and identifiers, such as Cell Global Identifiers (CGIs). Referring back to FIG. 4A , the failure recognition module 311 updates the NRT (SCG Failed PCI Information List) with the PCI of the second secondary node element 203-2. In steps 14 and 15, an SgNB release procedure and UE context release are performed after recognizing the failure. Referring back to FIG. 3 , in one example, consider that a UE generates a measurement report and indicates gNB1, which has PCI as “2,” as the target secondary node element. However, due to PCI confusion, gNB3 may be associated with the same PCI, i.e., “2.” In such a case, the first secondary node element 203-1 may identify gNB3 as the second secondary node element 203-2, causing a failure. The failure recognition module 311 may record in the NRT that the two PCIs are associated with PCI confusion. Data regarding the recognition of the failure may be stored in the memory 302 as failure data 307. Embodiments of the present disclosure enable recognition that the failure is due to PCI confusion, which helps to avoid such failures for future handovers. Furthermore, embodiments of the present disclosure enable configuration of a timer at the primary node element 202 to ensure that the failure is recognized as PCI confusion before releasing the context of the UE 201. Also, embodiments of the present disclosure ensure that PCIs associated with PCI confusion are recorded in the NRT for taking necessary action when such PCIs are seen during future handovers.

[0037] In one embodiment, the mitigation module 312 may be configured to receive the failure data 307 from the failure recognition module 311. Further, the mitigation module 312 may be configured to perform a mitigation operation during a subsequent handover from a first secondary node element 203-1 to one of the plurality of secondary node elements 203 for one of the plurality of UEs in the wireless network. When a request for a subsequent handover from the first secondary node element 203-1 to one or more secondary node elements 203 is received, the mitigation module 312 may determine a PCI of the one of the plurality of secondary node elements 203. The mitigation module 312 may determine that the PCI of the one of the plurality of secondary node elements 203 is the same as the recognized PCI.

[0038] In such a case, the mitigation module 312 may request a cell global identifier (CGI) from one of the plurality of UEs for performing a subsequent handover because the PCI is associated with the PCI confusion. Typically, a CGI is used to globally identify a cell in a network. The mitigation module 312 may receive the CGI from one of the plurality of UEs via the primary node element 202. Furthermore, upon receiving a response from one of the plurality of UEs, the mitigation module 312 may compare the CGI associated with the recognized PCI with the received CGI. The mitigation module 312 may detect that the failure is due to PCI confusion when the received CGI differs from the CGI associated with the recognized PCI. Referring to FIG. 4B, a handover is initiated in step 401, indicated by reference numeral 401. A failure is recognized, and the same PCI associated with the suspected or confirmed PCI is recorded in step 402, indicated by reference numeral 402. The failure is detected as a PCI confusion in step 403, indicated using the numeral 403, by receiving a CGI from the UE 201. Embodiments of the present disclosure enable detecting a PCI confusion by receiving a CGI from one of a plurality of UEs. This improves performance of the wireless network because the detection of a PCI confusion enables mitigation actions to be taken to avoid failures during future handovers. As a result, this improves quality of service to end users.

[0039] Referring back to FIG. 3 , in one embodiment, the mitigation module 312 may be configured to perform a mitigation operation during a subsequent handover of one of the plurality of UEs. Here, the mitigation module 312 may request a CGI from one of the plurality of UEs to perform the subsequent handover via the primary node element 202. Then, the mitigation module 312 may identify a secondary node element corresponding to the CGI from among the plurality of secondary node elements 203. Further, the mitigation module 312 may perform the subsequent handover from the first secondary node element 203-1 to the secondary node element. Thus, in the present disclosure, when a future handover request related to the recognized PCI is received, a CGI is received from one of the plurality of UEs to directly identify the actual secondary node element because the PCI is related to the PCI confusion.

[0040] Other data 309 may store data, including temporary data and temporary files, generated by one or more modules 305 for performing various functions of first secondary node element 203-1. Other data 309 may be stored in memory 302. One or more modules 305 may also include other modules 313 for performing various miscellaneous functions of first secondary node element 203-1.

[0041] FIG. 5 shows a diagram of a primary node element 202 for detecting PCI confusion during an SN change procedure in a wireless network, according to some embodiments of the present disclosure. The primary node element 202 may include an input / output (I / O) interface 501, a memory 502, and a central processing unit (also referred to as a CPU or processor 503). In some embodiments, the memory 502 may be communicatively coupled to the processor 503. The memory 502 stores instructions executable by the processor 503. The processor 503 may comprise at least one data processor for executing program components for executing user- or system-generated requests. The memory 502 may be communicatively coupled to the processor 503. The memory 502 stores instructions executable by the processor 503. The instructions, when executed, may cause the processor 503 to detect PCI confusion during an SN change procedure in a wireless network. The I / O interface 501 is coupled to the processor 503 for communicating input and / or output signals. For example, the SCG failure information may be sent to the first secondary node element 203-1 via the I / O interface 501. In one embodiment, the primary node element 202 may be implemented in a variety of computing systems, such as a server, a network server, and a cloud-based server.

[0042] In one embodiment, the primary node element 202 may configure a timer to retain the UE 201's context at the first secondary node element 203-1 for a predetermined period of time during handover of the UE 201 from the first secondary node element 203-1 to the second secondary node element 203-2. In one embodiment, the timer may be configured when the SgNB reconfiguration process is completed. In a conventional SN change procedure, the UE 201's context is released before the UE 201 completes the random access procedure. The present disclosure enables configuration of a timer at the primary node element 202 to retain the UE 201's context at the first secondary node element 203-1 to recognize and avoid failures during future handovers.

[0043] Additionally, the primary node element 202 may be configured to receive SCG failure information from the UE 201. The SCG failure information indicates the cause of the handover failure as a random access channel (RACH) failure. Embodiments of the present disclosure enable the first secondary node element 203-1 to receive the SCG failure along with the cause of the failure as a RACH failure, which helps to detect the failure.

[0044] The primary node element 202 may then send the SCG failure information to the first secondary node element 203-1. The first secondary node element 203-1 uses the SCG failure information to recognize, within a predetermined period of time, that the failure is due to a PCI confusion associated with the PCI of the second secondary node element (203-2). Furthermore, when the PCI of one secondary node element 203 of the multiple secondary node elements 203 is the same as the recognized PCI, the first secondary node element 203-1 performs mitigation actions during a subsequent handover from the first secondary node element 203-1 to the one secondary node element 203 of the multiple secondary node elements 203. Embodiments of the present disclosure ensure timely detection and avoidance of failures during SN change procedures, which improves user experience.

[0045] In one embodiment, the primary node element 202 is configured to send a request for a cell global identifier (CGI) received from the first secondary node element 203-1 to one of the plurality of UEs. In the present disclosure, the CGI is received from the UE 201 to help detect that the failure is due to PCI confusion and to perform a subsequent handover.

[0046] In one embodiment, the primary node element 202 is configured to send a message to the first secondary node element 203-1 after a predetermined period of time indicating (instructing) it to release the context of the UE 201. Embodiments of the present disclosure allow for delaying the message sent from the primary node element 202 to the first secondary node element 203-1 for a predetermined period associated with a timer to allow for recognizing that the failure is due to PCI confusion.

[0047] 6A shows an example flowchart illustrating method steps for detecting PCI confusion during an SN change procedure in a wireless network, according to some embodiments of the present disclosure. As shown in FIG. 6A, method 600 may include one or more steps. Method 600 may be described in the general context of computer-executable instructions. Generally, computer-executable instructions may include routines, programs, objects, components, data structures, procedures, modules, and functions that perform particular functions or implement particular abstract data types.

[0048] The order in which method 600 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to perform the method. Moreover, individual blocks may be deleted from the method without departing from the scope of the subject matter described herein. Furthermore, the method may be implemented in any suitable hardware, software, firmware, or combination thereof.

[0049] In step 601, SCG failure information may be received from the UE 201 via the primary node element 202. The SCG failure information may be received when a handover from a first secondary node element 203-1 to a second secondary node element 203-2 fails. The UE 201 may perform a random access procedure for the handover from the first secondary node element 203-1 to the second secondary node element 203-2, which may fail for various reasons. Then, SCG failure information may be received from the UE 201. The SCG failure information may indicate the cause of the failure as a RACH failure.

[0050] In step 602, a failure due to PCI confusion associated with the PCI of the second secondary node element 203-1 may be recognized. The failure may be recognized based on a cause of the failure as a RACH failure. The cause of the failure as a RACH failure provides an indication that the failure is due to PCI confusion. In one embodiment, the failure may be recognized within a predetermined period associated with a timer. In one embodiment, the PCI of the second secondary node element 203-2 may be recorded in the NRT of the first secondary node element 203-1 for the PCI confusion.

[0051] In step 603, mitigation operations may be performed for one of a plurality of UEs in the wireless network during a subsequent handover from a first secondary node element 203-1 to one of the plurality of secondary node elements 203. At the time of a subsequent handover request from the first secondary node element 203-1 to one or more secondary node elements 203, it may be determined that the PCI of the one of the plurality of secondary node elements 203 is the same as the recognized PCI. Next, a request for a CGI may be sent to the one of the plurality of UEs. Upon receiving a response from the one of the plurality of UEs, the CGI associated with the recognized PCI may be compared with the received CGI. When the received CGI differs from the CGI associated with the recognized PCI, a failure may be detected as being due to PCI confusion. Additionally, a secondary node element corresponding to the CGI may be identified from among the plurality of secondary node elements 203. Further, a subsequent handover from the first secondary node element 203-1 to the secondary node element may be performed.

[0052] 6B shows an example diagram for detecting PCI confusion during an SN change procedure in a centralized unit (CU) network. As shown, the S-SN recognizes that the failure is due to PCI confusion and therefore records the PCI so that mitigation actions can be taken during future handovers.

[0053] Computer Systems 7 illustrates a block diagram of an exemplary computer system 700 for implementing embodiments consistent with the present disclosure. In one embodiment, the computer system 700 may be used to implement the first secondary node element 203-1. In one embodiment, the computer system 700 may receive SCG failure information from the primary node element 202 via a communication network 709. The computer system 700 may include a central processing unit 702 (also referred to as a CPU or processor). The processor 702 may include at least one data processor. The processor 702 may include specialized processing units such as an integrated system (bus) controller, a memory management control unit, a floating-point unit, a graphics processing unit, a digital signal processing unit, etc.

[0054] The processor 702 may be arranged to communicate with one or more input / output (I / O) devices (not shown) via an I / O interface 701 . The I / O interface 701 may use communication protocols / methods such as, but not limited to, audio, analog, digital, mono, RCA, stereo, IEEE (Institute of Electrical and Electronics Engineers) 1394, serial bus, universal serial bus (USB), infrared, PS / 2, BNC, coaxial, component, composite, digital visual interface (DVI), high-definition multimedia interface (HDMI), radio frequency (RF) antenna, S-video, VGA, IEEE 802.n / b / g / n / x, Bluetooth, cellular (e.g., code-division multiple access (CDMA), high-speed packet access (HSPA+), global system for mobile communications (GSM), long-term evolution (LTE), or WiMax).

[0055] Using I / O interface 701, computer system 700 may communicate with one or more I / O devices. For example, input device(s) 710 may be an antenna, keyboard, mouse, joystick, (infrared) remote control, camera, card reader, fax machine, dongle, biometric reader, microphone, touch screen, touch pad, trackball, stylus, scanner, storage device, transceiver, video device / source, sensor, etc. Output device(s) 711 may be a printer, fax machine, video display (e.g., cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), plasma, plasma display panel (PDP), or organic light-emitting diode display (OLED), etc.), audio speaker, etc.

[0056] The processor 702 may be arranged to communicate with a communications network 709 via a network interface 703. The network interface 703 may communicate with the communications network 709. The network interface 703 may use a connection protocol including, but not limited to, a direct connection, Ethernet (e.g., twisted pair 10 / 100 / 1000 Base-T), Transmission Control Protocol / Internet Protocol (TCP / IP), Token Ring, IEEE 802.11a / b / g / n / x, etc. The communications network 709 may include, but is not limited to, a direct interconnect, a local area network (LAN), a wide area network (WAN), a wireless network (e.g., using a wireless application protocol), the Internet, etc. The network interface 703 may use connection protocols including, but not limited to, direct connect, Ethernet (e.g., twisted pair 10 / 100 / 1000 Base-T), Transmission Control Protocol / Internet Protocol (TCP / IP), Token Ring, IEEE 802.11a / b / g / n / x, Bluetooth mesh, Zigbee, etc.

[0057] The communications network 709 may include, but is not limited to, direct interconnections, electronic commerce networks, peer-to-peer (P2P) networks, local area networks (LANs), wide area networks (WANs), wireless networks (e.g., using Wireless Application Protocol), the Internet, Wi-Fi, etc. The first and second networks may be either dedicated networks or shared networks representing federations of different types of networks that communicate with each other using various protocols, e.g., Hypertext Transfer Protocol (HTTP), Transmission Control Protocol / Internet Protocol (TCP / IP), Wireless Application Protocol (WAP), etc. Additionally, the first and second networks may include various network devices, including routers, bridges, servers, computing devices, storage devices, etc.

[0058] In some embodiments, the processor 702 may be arranged to communicate with memory 705 (e.g., RAM, ROM, etc., not shown in FIG. 7 ) via a storage interface 704. The storage interface 704 may connect to memory 705 including, but not limited to, memory drives, removable disk drives, etc., using connection protocols such as Serial Advanced Technology Attachment (SATA), Integrated Drive Electronics (IDE), IEEE 1394, Universal Serial Bus (USB), Fibre Channel, Small Computer Systems Interface (SCSI), etc. The memory drives may further include drum, magnetic disk drives, magneto-optical drives, optical drives, redundant array of independent disks (RAID), solid state memory devices, solid state drives, etc.

[0059] Memory 705 may store a collection of program or database components, including, but not limited to, a user interface 706, an operating system 707, a web browser 708, etc. In some embodiments, computer system 700 may store user / application data, such as data, variables, records, etc., as described in this disclosure. Such databases may be implemented as fault-tolerant, relational, scalable, secure databases, such as Oracle® or Sybase®.

[0060] Operating system 707 may facilitate resource management and operation of computer system 700. Examples of operating systems include, but are not limited to, APPLE MACINTOSH® OS X, UNIX®, UNIX-like system distributions (e.g., BERKELEY SOFTWARE DISTRIBUTION™ (BSD), FREEBSD™, NETBSD™, OPENBSD™, etc.), LINUX DISTRIBUTIONS™ (e.g., RED HAT™, UBUNTU™, KUBUNTU™, etc.), IBM™ OS / 2, MICROSOFT™ WINDOWS® (XP™, VIST™ / 7 / 8, 10, etc.), APPLE® IOS™, GOOGLE® ANDROID®, or BLACKBERRY® OS, etc.

[0061] In some embodiments, computer system 700 may implement a program component stored on web browser 708. Web browser 708 may be a hypertext browsing application such as MICROSOFT® INTERNET EXPLORER™, GOOGLE® CHROME TM0, MOZILLA® FIREFOX™, APPLE® SAFARI™, etc. Secure web browsing may be provided using Secure Hypertext Transport Protocol (HTTPS), Secure Sockets Layer (SSL), Transport Layer Security (TLS), etc. Web browser 708 may utilize features such as AJAX™, DHTML™, ADOBE® FLASH™, JAVASCRIPT®, JAVA®, Application Programming Interfaces (APIs), etc. In some embodiments, computer system 700 may implement a program component stored on a mail server (not shown). The mail server may be an Internet mail server such as Microsoft Exchange. The mail server may utilize functionality such as ASP™, ACTIVEX™, ANSI™ C++ / C#, MICROSOFT® .NET™, CGI SCRIPTS™, JAVA™, JAVASCRIPT™, PERL™, PHP™, PYTHON®, WEBOBJECTS™, etc. The mail server may utilize communication protocols such as Internet Message Access Protocol (IMAP), Messaging Application Programming Interface (MAPI), MICROSOFT® exchange, Post Office Protocol (POP), or Simple Mail Transfer Protocol (SMTP). In some embodiments, computer system 700 may implement a mail client stored program component.The email client (not shown) may be an email viewing application such as APPLE® MAIL™, MICROSOFT® ENTOURAGE™, MICROSOFT® OUTLOOK™, MOZILLA® THUNDERBIRD™, or the like.

[0062] Additionally, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present disclosure. A computer-readable storage medium refers to any type of physical memory in which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor to perform steps or stages consistent with the embodiments described herein. The term "computer-readable medium" should be understood to include tangible articles and exclude carrier waves and transient signals, i.e., non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, non-volatile memory, hard drives, compact disc read-only memory (CD ROM), digital video discs (DVDs), flash drives, disks, and any other known physical storage medium.

[0063] Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present disclosure. A computer-readable storage medium refers to any type of physical memory in which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor to perform steps or stages consistent with the embodiments described herein. The term "computer-readable medium" should be understood to include tangible articles and exclude carrier waves and transient signals, i.e., non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, non-volatile memory, hard drives, CD (compact disc) ROMs, DVDs, flash drives, disks, and any other known physical storage medium.

[0064] In one embodiment, a first secondary node element 203-1 is disclosed. The first secondary node element 203-1 includes a processor 303 and a memory 302. The processor is configured to receive SCG failure information from the UE 201 via the primary node element 202 during handover of the UE 201 from the first secondary node element 203-1 to the second secondary node element 203-2. The SCG failure information indicates a cause of the handover failure as a RACH failure. Furthermore, the first secondary node element 203-1 recognizes, based on the cause, that the failure is due to PCI confusion related to the PCI of the second secondary node element 203-2 within a predetermined period associated with a timer configured in the primary node element 202 to retain the context of the UE 201 in the first secondary node element 203-1. Thereafter, the first secondary node element 203-1 performs a mitigation operation during a subsequent handover from the first secondary node element 203-1 to one secondary node element 203 of the plurality of secondary node elements 203 for one UE of the plurality of UEs in the wireless network when the PCI of the one secondary node element 203 of the plurality of secondary node elements 203 is the same as the recognized PCI.

[0065] In one embodiment, the processor 303 is configured to request a CGI for performing a subsequent handover from one of the plurality of UEs when the PCI of one of the plurality of secondary node elements 203 is the same as the recognized PCI. Further, the processor 303 is configured, upon receiving a response from one of the plurality of UEs, to compare the CGI associated with the recognized PCI with the received CGI. Further, the processor 303 is configured to detect, based on the comparison, that the failure is due to PCI confusion.

[0066] In one embodiment, the processor 303 is configured to perform a mitigation operation during a subsequent handover of one of the plurality of UEs by requesting the CGI from one of the plurality of UEs via the primary node element 202. Further, the processor 303 is configured to identify a secondary node element corresponding to the CGI from among the plurality of secondary node elements 203. Further, the processor 303 is configured to perform a subsequent handover from the first secondary node element 203-1 to the secondary node element.

[0067] In one embodiment, the processor 303 is configured to record the PCI confusion for the PCI of the second secondary node element 203-2 in the NRT of the first secondary node element 203-1 upon recognizing that the failure is due to a PCI confusion.

[0068] In one embodiment, a primary node element 202 is disclosed. The primary node element includes a processor 503 and a memory 502. The processor configures a timer to retain a context of the UE 201 in the first secondary node element 203-1 for a predetermined period during handover of the UE 201 from the first secondary node element 203-1 to the second secondary node element 203-2. Further, the processor is configured to receive SCG failure information from the UE 201. The SCG failure information indicates a cause of the handover failure as a random access channel (RACH) failure. Further, the processor is configured to transmit the SCG failure information to the first secondary node element 203-1. The first secondary node element 203-1 recognizes, within a predetermined period of time, that the failure is due to PCI confusion associated with the PCI of the second secondary node element 203-2, and uses the SCG failure information to perform mitigation actions during a subsequent handover from the first secondary node element 203-1 to the one secondary node element 203 of the multiple secondary node elements 203 for one UE of the multiple UEs in the wireless network when the PCI of the one secondary node element 203 of the multiple secondary node elements 203 is the same as the recognized PCI.

[0069] In one embodiment, a method is disclosed. The method includes receiving SCG failure information from a UE 201 via a primary node element 202 during handover of the UE 201 from a first secondary node element 203-1 to a second secondary node element 203-2. The SCG failure information indicates a cause of the handover failure as a RACH failure. The method further includes recognizing, based on the cause, within a predetermined period associated with a timer configured in the primary node element 202 for maintaining the UE 201's context in the first secondary node element 203-1 that the failure is due to PCI confusion associated with the PCI of the second secondary node element 203-2. The method further includes performing a mitigation action during a subsequent handover from the first secondary node element 203-1 to one of the multiple secondary node elements 203 for one of the multiple UEs in the wireless network when the PCI of the one of the multiple secondary node elements 203 is the same as the recognized PCI.

[0070] The terms "an embodiment," "embodiment," "embodiments," "the embodiment," "the embodiment," "the illustration," "one or more illustrations," "some illustrations," and "one embodiment" mean "one or more (but not all) embodiments of the present invention," unless expressly stated otherwise.

[0071] The terms "including," "comprising," and "having," and variations thereof, mean "including, but not limited to," unless expressly stated otherwise.

[0072] An enumerated list of things does not imply that any or all of the things are mutually exclusive unless expressly stated otherwise. The terms "a," "an," and "the" mean "one or more" unless expressly stated otherwise.

[0073] A description of an embodiment having several components in communication with each other does not imply that all such components are required. On the contrary, various optional components are described to illustrate the wide variety of possible embodiments of the present invention.

[0074] It is readily apparent that when a single device or article is described herein, more than one device / article (whether they cooperate or not) may be used in place of the single device / article. Similarly, when more than one device or article is described herein (whether they cooperate or not), it is readily apparent that a single device / article may be used in place of more than one device or article, or that a different number of devices / articles may be used in place of the illustrated number of devices or programs. The functionality and / or features of a device may alternatively be embodied by one or more other devices not explicitly described as having such functionality / features. Thus, other embodiments of the present invention need not include the device itself.

[0075] The illustrated operations in Figure 6 show certain events occurring in a particular order. In alternative embodiments, certain operations may be performed in a different order, modified, or removed (omitted). Furthermore, additional steps may be added to the logic (methods, operations, steps) described above and still be compatible with the above embodiments. Furthermore, operations described herein may be performed sequentially, or certain operations may be processed (performed) in parallel. Furthermore, operations may be performed by a single processing unit or distributed processing units.

[0076] Finally, the language used herein has been chosen primarily for ease of reading and instructional purposes, and may not be chosen to delineate or limit the subject matter of the present invention. Accordingly, it is intended that the scope of the invention be limited not by this detailed description, but by the claims filed hereunder. Accordingly, the disclosure of embodiments of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[0077] While various aspects and embodiments are disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, the true scope being indicated by the following claims.

Claims

1. A first secondary node element (203-1), a memory (302) configured to store instructions executable by a processor (303); the processor (303), which executes the instructions stored in the memory (302), thereby causing the first secondary node element (203-1) to: During handover of the user equipment (UE) (201) from the first secondary node element (203-1) to the second secondary node element (203-2), receive secondary cell group (SCG) failure information from the UE (201) via the primary node element (202), the SCG failure information indicating a cause of the handover failure as a random access channel (RACH) failure; and recognizing, based on the cause, that the failure is due to a physical cell identifier (PCI) confusion associated with a PCI of the second secondary node element (203-2) within a predetermined period associated with a timer configured in the primary node element (202) for maintaining the context of the UE (201) in the first secondary node element (203-1); performing a mitigation action during a subsequent handover from the first secondary node element (203-1) to one of the plurality of secondary node elements (203) for one of a plurality of UEs in a wireless network when the PCI of the one of the plurality of secondary node elements (203) is the same as the recognized PCI; It was configured as follows: A first secondary node element (203-1).

2. When the PCI of one secondary node element (203) among the plurality of secondary node elements (203) is the same as the recognized PCI, Requesting a Cell Global Identifier (CGI) from one of the plurality of UEs via the primary node element (202) for performing the subsequent handover; Upon receiving a response from one of the plurality of UEs, comparing a CGI associated with the recognized PCI with the received CGI; detecting, based on the comparison, that the failure is due to the PCI confusion; The first secondary node element (203-1) of claim 1, configured as follows:

3. The processor (303) is configured to perform the mitigation action during the subsequent handover of one UE of the plurality of UEs, the mitigation action comprising: requesting, via the primary node element (202), a CGI from one of the plurality of UEs for performing the subsequent handover; Identifying a secondary node element corresponding to the CGI from among the plurality of secondary node elements (203); and performing the subsequent handover from the first secondary node element (203-1) to the secondary node element; The first secondary node element (203-1) of claim 1, executed by:

4. The first secondary node element (203-1) of claim 1, wherein the processor (303) is configured to record the PCI confusion for the PCI of the second secondary node element (203-2) in an adjacency relation table (NRT) of the first secondary node element (203-1) upon recognizing that the failure is due to the PCI confusion.

5. A primary node element (202), a memory (502) configured to store instructions executable by a processor (503); the processor (503), which executes the instructions stored in the memory (502), thereby causing the primary node element (202) to: configuring a timer to retain a context of a user equipment (UE) (201) in the first secondary node element (203-1) for a predetermined period during handover of the UE (201) from the first secondary node element (203-1) to a second secondary node element (203-2); Receive secondary cell group (SCG) failure information from the UE (201), the SCG failure information indicating the cause of the handover failure as a random access channel (RACH) failure; configured to cause the SCG failure information to be transmitted to the first secondary node element (203-1); the first secondary node element (203-1) uses the SCG failure information to recognize, within the predetermined period of time, that the failure is due to a physical cell identifier (PCI) confusion associated with a PCI of the second secondary node element (203-2); and further uses the SCG failure information to perform mitigation actions during a subsequent handover from the first secondary node element (203-1) to one secondary node element (203) of the plurality of secondary node elements (203) for one UE of a plurality of UEs in a wireless network when the PCI of the one secondary node element (203) of the plurality of secondary node elements (203) is the same as the recognized PCI. Primary node element (202).

6. The primary node element (202) of claim 5, wherein the processor (503) is configured to send a request for a cell global identifier (CGI) received from the first secondary node element (203-1) to one of the plurality of UEs.

7. The primary node element (202) of claim 5, wherein the processor (503) is configured to send a message to the first secondary node element (203-1) indicating to release the context of the UE (201) after the predetermined period.

8. 1. A method comprising: receiving, by the first secondary node element (203-1), during handover of the user equipment (UE) (201) from the first secondary node element (203-1) to a second secondary node element (203-2), secondary cell group (SCG) failure information from the UE (201) via a primary node element (202), wherein the SCG failure information indicates a cause of the handover failure as a random access channel (RACH) failure; The method comprises: and recognizing, by the first secondary node element (203-1), within a predetermined period related to a timer configured in the primary node element (202) for maintaining the context of the UE (201) in the first secondary node element (203-1), based on the cause, that the failure is due to a physical cell identifier (PCI) confusion related to a PCI of the second secondary node element (203-2); performing, by the first secondary node element (203-1), a mitigation operation during a subsequent handover for one of a plurality of UEs in a wireless network from the first secondary node element (203-1) to one of the plurality of secondary node elements (203) when the PCI of the one of the plurality of secondary node elements (203) is the same as the recognized PCI; A method comprising:

9. When the PCI of one secondary node element (203) among the plurality of secondary node elements (203) is the same as the recognized PCI, the method includes: requesting, via the primary node element (202), from one UE of the plurality of UEs a Cell Global Identifier (CGI) for performing the subsequent handover; Upon receiving a response from one of the plurality of UEs, comparing a CGI associated with the recognized PCI with the received CGI; detecting, based on the comparison, that the failure is due to PCI confusion; The method of claim 8, comprising:

10. performing the mitigation action during the subsequent handover of one UE of the plurality of UEs, requesting, via the primary node element (202), from one UE of the plurality of UEs a CGI for performing the subsequent handover; identifying a secondary node element corresponding to the CGI from among the plurality of secondary node elements (203); performing the subsequent handover from the first secondary node element (203-1) to the secondary node element; The method of claim 8, comprising:

11. Upon identifying that the failure is due to the PCI confusion, the method:

9. The method of claim 8, further comprising the step of recording the PCI confusion for the PCI of the second secondary node element (203-2) in a neighbor relation table (NRT) of the first secondary node element (203-1).

12. A non-transitory computer-readable medium containing instructions for performing operations, the operations comprising: receiving secondary cell group (SCG) failure information from a user equipment (UE) (201) via the primary node element (202) during handover of the UE (201) from a first secondary node element (203-1) to a second secondary node element (203-2), wherein the SCG failure information indicates a cause of the handover failure as a random access channel (RACH) failure; The operation is and recognizing, based on the cause, that the failure is due to a Physical Cell Identifier (PCI) confusion associated with a PCI of the second secondary node element (203-2) within a predetermined period associated with a timer configured in the primary node element (202) for maintaining the context of the UE (201) in the first secondary node element (203-1); performing a mitigation operation during a subsequent handover from the first secondary node element (203-1) to one of the plurality of secondary node elements (203) for one of a plurality of UEs in a wireless network when the PCI of the one of the plurality of secondary node elements (203) is the same as the recognized PCI; 1. A non-transitory computer-readable medium comprising:

13. When the PCI of one secondary node element (203) among the plurality of secondary node elements (203) is the same as the recognized PCI, requesting, via the primary node element (202), from one UE of the plurality of UEs a Cell Global Identifier (CGI) for performing the subsequent handover; Upon receiving a response from one of the plurality of UEs, comparing a CGI associated with the recognized PCI with the received CGI; detecting, based on the comparison, that the failure is due to PCI confusion; The medium of claim 12, comprising:

14. performing the mitigation action during the subsequent handover of one UE of the plurality of UEs, requesting, via the primary node element (202), from one UE of the plurality of UEs a CGI for performing the subsequent handover; identifying a secondary node element corresponding to the CGI from among the plurality of secondary node elements (203); performing the subsequent handover from the first secondary node element (203-1) to the secondary node element; The medium of claim 12, comprising:

15. Once you have determined that the failure was due to the PCI confusion, 13. The medium of claim 12, further comprising recording the PCI confusion for the PCI of the second secondary node element (203-2) in a neighbor relation table (NRT) of the first secondary node element (203-1).

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