Methods to avoid l-CP and CU-CP conflicts

Abstract

A method, apparatus, and computer program product are provided. In the context of a method, the method includes receiving, from a user equipment or a centralized network node, a message, wherein a message header of the message comprises a flag indicating that the message is for inter-centralized unit handover. The method includes reading the flag. The method includes determining, based at least on the flag, whether to transmit or not to transmit the message to one of the user equipment or the centralized network node to perform the inter-centralized unit handover or not.

Description

METHODS TO AVOID L-CP AND CU-CP CONFLICTSTECHNOLOGICAL FIELD

[0001] An example embodiment relates generally to avoiding conflicts during conditional handover and, more particularly, to avoiding conflict between intra-centralized unit handover and inter-centralized unit handover.BACKGROUND

[0002] A network node may consist of a centralized network node and one or more distributed network node. Splitting the network node into a centralized network node and distributed network nodes allows better scalability, flexibility, and enhanced network efficiency. In addition, splitting a network node into a centralized network node and one or more distributed network nodes enables cloud native architecture deployment where a centralized network node can be deployed at the edge cloud and the distributed units can be deployed at a far edge cloud.

[0003] A centralized unit control plane controls and handles all inter-centralized network node (or inter-centralized unit) procedures. For example, a centralized unit control plane configures and receives measurements related to inter-centralized unit handovers, inter-radio access technology handovers, dual connectivity, and the like. A centralized unit control plane synchronizes with a local control plane (responsible for intra-centralized unit functionalities) after and during inter-centralized unit procedures (e.g., user equipment context release).

[0004] A local control plane may coordinate with or notify a centralized unit control plane before or after events which it handles. For example, the local control plane may handle conditional handover, lower layer mobility, inter-distributed unit (or intra-centralized unit handover, carrier aggregation, and the like.

[0005] A centralized unit control plane may fetch the latest user equipment radio resource control configuration from a local control plane while initiating inter-centralized unit procedures. Alternatively, the local control plane may synchronize with the centralized unit control place after completion of each radio resource control procedure.

[0006] There is currently no mechanism which addresses a scenario where the network nodes (i.e., local control plane and centralized unit control plane) receive reports from the user equipment and simultaneously start two baseline handover preparations. In addition, there is nomechanism which addresses a scenario where two conditional handovers are received by a user equipment, one from the local control plane and the other from the centralized unit control plane. A new method is needed to mitigate the occurrence of these scenarios so that resources aren’t wasted preparing a handover that does not take place.BRIEF SUMMARY

[0007] In one or more embodiments, a distributed network node (112) is provided including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the distributed network node (112) to receive (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for inter-centralized unit (114 / 118) handover. The distributed network node (112) is further caused to read the flag (504b / 912b). The distributed network node (112) is further caused to determine (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the intercentralized unit (114 / 118) handover or not.

[0008] In one or more embodiments, a user equipment (110) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the user equipment (110) to add, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The user equipment (110) is further caused to transmit (504), to a distributed network node (112), the measurement report message (504a).

[0009] In one or more embodiments, a user equipment (110) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the user equipment (110) to receive (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover.

[0010] In one or more embodiments, a centralized network node (114) is provided, including at least one processor and at least one memory storing instructions that, when executed by theprocessor, cause the centralized network node (114) to add, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The centralized network node (114) is further caused to transmit (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0011] In one or more embodiments, a centralized network node (114) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the centralized network node (114) to receive (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The centralized network node (114) is further caused to determine (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.

[0012] In one or more embodiments, a computer-implemented method is provided that is performed by a distributed network node (112) and includes receiving (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for intercentralized unit (114 / 118) handover. The method further includes reading the flag (504b / 912b). The method further includes determining (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the inter-centralized unit (114 / 118) handover or not.

[0013] In one or more embodiments, a computer-implemented method is provided that is performed by a user equipment (110) and includes adding, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The method further includes transmitting (504), to a distributed network node (112), the measurement report message (504a).

[0014] In one or more embodiments, a computer-implemented method is provided that is performed by a user equipment (110) and includes receiving (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicatingthat the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover .

[0015] In one or more embodiments, a computer-implemented method is provided that is performed by a centralized network node (114) and includes adding, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The method includes transmitting (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0016] In one or more embodiments, a computer-implemented method is provided that is performed by a centralized network node (114) and includes receiving (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The method further includes determining (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.

[0017] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a distributed network node (112), cause the distributed network node (112) to receive (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for inter-centralized unit (114 / 118) handover. The distributed network node (112) is further caused to read the flag (504b / 912b). The distributed network node (112) is further caused to determine (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the intercentralized unit (114 / 118) handover or not.

[0018] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to add, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The user equipment (110) is further caused to transmit (504), to a distributed network node (112), the measurement report message (504a).

[0019] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to receive (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover .

[0020] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to add, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The centralized network node (114) is further caused to transmit (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0021] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to receive (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The centralized network node (114) is further caused to determine (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.

[0022] In one or more embodiments, a distributed network node (112) is provided that includes means for receiving (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for inter-centralized unit (114 / 118) handover. The distributed network node (112) further includes means for reading the flag (504b / 912b). The distributed network node further includes means for determining (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the inter-centralized unit (114 / 118) handover or not.

[0023] In one or more embodiments, a user equipment (110) is provided that includes means for adding, to a message header of a measurement report message (504a), a flag (504b), wherein theflag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The user equipment (110) further includes means for transmitting (504), to a distributed network node (112), the measurement report message (504a).

[0024] In one or more embodiments, a user equipment (110) is provided that includes means for receiving (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover .

[0025] In one or more embodiments, a centralized network node (114) is provided that includes means for adding, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The centralized network node (114) includes means for transmitting (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0026] In one or more embodiments, a centralized network node (114) is provided that includes means for receiving (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The centralized network node (114) includes means for determining (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Having thus described certain example embodiments of the present disclosure in general terms, reference will hereinafter be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0028] FIG. 1 is a block diagram of a system including a user equipment, distributed network nodes, and centralized network nodes configured to communicate at least via uplink and downlink transmission in accordance with an example embodiment of the present disclosure;

[0029] FIG. 2 is a block diagram of an example communication system in which the system of FIG. 1 may be deployed in accordance with an example embodiment of the present disclosure;

[0030] FIG. 3 is a signaling diagram for intra-centralized unit handover and inter-centralized unit handover in a dual radio resource control scenario in accordance with previous embodiments.

[0031] FIG. 4A is a signaling diagram illustrating simultaneous triggering of intra-centralized unit handover and inter-centralized unit handover in a dual radio resource control scenario in accordance with previous embodiments.

[0032] FIG. 4B is an illustration of inter-centralized unit handover and intra-centralized unit handover in a dual radio resource control scenario in accordance with previous embodiments.

[0033] FIG. 4C is a signaling diagram illustrating user equipment-triggered handover with the user equipment receiving two radio resource control reconfigurations in accordance with previous embodiments.

[0034] FIG. 5A is a signaling diagram illustrating a user equipment adding a flag to a message to message to the distributed network node and the distributed network node reading the flag in accordance with example embodiments of the present disclosure.

[0035] FIG. 5B is a signaling diagram illustrating a distributed network node intercepting and reading a message from a user equipment in accordance with example embodiments of the present disclosure.

[0036] FIG. 6A is a signaling diagram illustrating a distributed network node reading a flag from a user equipment after a handover in accordance with example embodiments of the present disclosure.

[0037] FIG. 6B is a signaling diagram illustrating a distributed network node intercepting and reading a message from a user equipment after a handover in accordance with example embodiments of the present disclosure.

[0038] FIG. 7A is a signaling diagram illustrating a distributed network node reading a flag from a user equipment and forwarding an enhanced message to a centralized network node in accordance with example embodiments of the present disclosure.

[0039] FIG. 7B is a signaling diagram illustrating a distributed network node intercepting and reading a message from a user equipment, enhancing the message, and forwarding the message to a centralized network node in accordance with example embodiments of the present disclosure.

[0040] FIG. 8A is a signaling diagram illustrating a distributed network node reading a flag from a user equipment when there is no ongoing intra-centralized unit handover in accordance with example embodiments of the present disclosure.

[0041] FIG. 8B is a signaling diagram illustrating a distributed network node intercepting and reading a message from a user equipment when there is no ongoing intra centralized unit handover in accordance with example embodiments of the present disclosure.

[0042] FIG. 9A is a signaling diagram illustrating a distributed network node reading a flag from a centralized unit in accordance with example embodiments of the present disclosure.

[0043] FIG. 9B is a signaling diagram illustrating a distributed network node intercepting and reading a message from a centralized unit (CU) in accordance with example embodiments of the present disclosure.

[0044] FIG. 10 is a flowchart illustrating processes performed by a user equipment, a distributed network node, and a centralized network node to prepare for inter-centralized unit handover or intra-centralized unit handover in accordance with example embodiments of the present disclosure.

[0045] FIG. 11 is a signaling diagram illustrating a centralized network node preparing conditional handover configurations and a distributed network node avoiding preparation for conditional handover in accordance with example embodiments of the present disclosure.

[0046] FIG. 12 is a signaling diagram illustrating a centralized network node preparing conditional handover configurations and a user equipment avoiding reporting intra-centralized network node measurements in accordance with example embodiments of the present disclosure.

[0047] FIG. 13 is a signaling diagram illustrating a distributed network node instructing a user equipment to report only to a centralized network node in accordance with example embodiments of the present disclosure.

[0048] FIG. 14 is a flowchart illustrating processes performed by a user equipment, a distributed network node, and a centralized network node when a user equipment is at a border area of the distributed network node in accordance with example embodiments of the present disclosure.

[0049] FIG. 15 is a signaling diagram illustrating a distributed network node comparing signal levels of intra-centralized unit cells and inter-centralized unit cells in accordance with example embodiments of the present disclosure.

[0050] FIG. 16 is a signaling diagram illustrating a user equipment modifying intra-centralized unit conditional handover execution conditions in accordance with example embodiments of the present disclosure.

[0051] FIG. 17 is a flowchart illustrating processes performed by a user equipment, a distributed network node, and a centralized network node when the distributed unit compares intracentralized unit cell quality and inter-centralized unit cell quality in accordance with example embodiments of the present disclosure.

[0052] FIG. 18 is a flowchart demonstrating operations performed by a distributed network node in order to determine whether to transmit a message in accordance with example embodiments of the present disclosure.

[0053] FIG. 19 is a flowchart illustrating processes performed by a distributed network node in order to transmit an enhanced message to a centralized network node in accordance with example embodiments of the present disclosure.

[0054] FIG. 20 is a flowchart illustrating processes performed by a distributed network node in order to avoid intra-centralized unit handover preparation during inter-centralized handover in accordance with example embodiments of the present disclosure.

[0055] FIG. 21 is a flowchart illustrating processes performed by a distributed network node in order to determine whether a user equipment is at a border area of a serving cell in accordance with example embodiments of the present disclosure.

[0056] FIG. 22 is a flowchart illustrating processes performed by a distributed network node in order to disregard a measurement report message in accordance with example embodiments of the present disclosure.

[0057] FIG. 23 is a flowchart illustrating processes performed by a distributed network node in order to determine whether a user equipment is at a border of a serving area in accordance with example embodiments of the present disclosure.

[0058] FIG. 24 is a flowchart illustrating processes performed by a distributed network node in order to initiate an intra-centralized unit conditional handover preparation in accordance with example embodiments of the present disclosure.

[0059] FIG. 25 is a flowchart illustrating processes performed by a user equipment in order to add a flag to a message header of a measurement report message and transmit the message in accordance with example embodiments of the present disclosure.

[0060] FIG. 26 is a flowchart illustrating processes performed by a user equipment in order to report measurements to only a centralized network node or a distributed network node in accordance with example embodiments of the present disclosure.

[0061] FIG. 27 is a flowchart illustrating processes performed by a centralized network node in order to add a flag to a message header of a radio resource control reconfiguration message and transmit the flagged message in accordance with example embodiments of the present disclosure.

[0062] FIG. 28 is a flowchart illustrating processes performed by a centralized network node in order to determine whether to initiate an inter-centralized unit handover in accordance with example embodiments of the present disclosure.

[0063] FIG. 29 is a flowchart illustrating processes performed by a centralized network node in order to determine whether to initiate an intra-centralized unit handover or inter-centralized unit handover in accordance with example embodiments of the present disclosure.

[0064] FIG. 30 is a flowchart illustrating processes performed by a distributed network node in order to transmit or not transmit a message based on whether inter-centralized unit cells have a better signal level than intra-centralized unit cells in accordance with example embodiments of the present disclosure.

[0065] FIG. 31 is a flowchart illustrating processes performed by a user equipment in order to modify execution conditions in accordance with example embodiments of the present disclosure.

[0066] FIG. 32 is a flowchart illustrating processes performed by a centralized network node in order to determine and transmit a configuration for intra-centralized unit conditional handover modification in accordance with example embodiments of the present disclosure.DETAILED DESCRIPTION

[0067] Some embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, various embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. As used herein, the terms “data,” “content,” “information,” and similar terms may be used interchangeably to refer to data capable of being transmitted, received and / or stored in accordance with embodiments of the present disclosure.Thus, use of any such terms should not be taken to limit the spirit and scope of embodiments of the present disclosure.

[0068] Additionally, as used herein, the term “circuitry” refers to (a) hardware-only circuit implementations (e.g., implementations in analog circuitry and / or digital circuitry); (b) combinations of circuits and computer program product(s) including software and / or firmware instructions stored on one or more computer readable memories that work together to cause an apparatus to perform one or more functions described herein; and (c) circuits, such as, for example, a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation even if the software or firmware is not physically present. This definition of “circuitry” applies to all uses of this term herein, including in any claims. As a further example, as used herein, the term “circuitry” also includes an implementation including one or more processors and / or portion(s) thereof and accompanying software and / or firmware. As another example, the term “circuitry” as used herein also includes, for example, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, other network device (such as a core network apparatus), field programmable gate array, and / or other computing device.

[0069] As used herein, the term “computer-readable medium” refers to non-transitory storage hardware, non-transitory storage device or non-transitory computer system memory that may be accessed by a controller, a microcontroller, a computational system or a module of a computational system to encored thereon computer-executable instructions or software programs. A non-transitory “computer readable medium” may be accessed by a computational system or a module of a computational system to retrieve and / or execute the computerexecutable instructions or software programs encoded on the medium. Examples of non- transitory computer-readable media may include, but are not limited to, one or more types of hardware memory, non-transitory tangible media (for example, one or more magnetic storage disks, one or more optical disks, one or more universal synchronous bus (USB) flash drives), computer system memory or random-access memory (such as dynamic random access memory (DRAM), static random access memory (SRAM), extended data out random access memory (EDO RAM), and the like.

[0070] As illustrated in FIG. 1, a system 100 is provided in accordance with an example embodiment in order to avoid local control plane and centralized unit control plane conflicts.Although the system may be configured in various manners, the system of one embodiment is depicted in FIG. 1 and includes user equipment 110, distributed network nodes 112, 116, and 120, and centralized network nodes 114 and 118 configured to communicate via uplink and downlink transmission and reception beams. Although one user equipment, three distributed network nodes, and two centralized network nodes are depicted, the system may include and the user equipment 110, distributed network nodes 112, 116, and 120 ,and centralized network nodes 114 and 118 may communicate with additional user equipment, distributed network nodes, and centralized network nodes in other embodiments. In one or more embodiments, the user equipment 110, distributed network nodes 112, 116, and 120, and centralized network nodes 114 and 118 may be configured to support, for example, 5G, 5G advanced, or 6G. In one or more embodiments, the system 100 may support carrier aggregation and / or dual connectivity. As described below, the system may support paging triggered small data transmission, such as mobile terminated small data transmission and / or mobile originated small data transmission.

[0071] The data that is transmitted via the uplink and downlink beams between the user equipment 110, distributed network nodes 112, 116, and 120, and centralized network nodes 114 and 118 may be any of a wide variety of data including, but not limited to digital imagery data including video data, audio data as well as data provided by sensors, radars, telescopes and radio receivers. In at least some instances, the data is encoded prior to communication of the data via the uplink and downlink beams and decoded upon reception. The resulting data received may be utilized for a variety of purposes including presentation to a user, storage of the data for subsequent use and / or provision of the data to one or more applications, such as applications that perform statistical inference on the data for various purposes including object recognition, image classification, spectrum sensing, speech transcription and / or prediction or detection of events.

[0072] The user equipment 110 of FIG. 1 (also called UE, user device, user terminal, terminal device, etc.) illustrates a type of an apparatus which resources on an air interface are allocated and assigned. The user equipment 110 typically refers to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (mobile phone), smartphone, personal digital assistance (PDA), handset, device using a wireless modem (alarm or measurement device, etc.), laptop and / or touch screen computer, tablet, game console, notebook, and multimedia device. User equipment 110 may alsobe a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction. The user equipment 110 may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal, or user equipment (UE) just to mention but a few names or apparatuses. The user equipment 110 may be connected via radio resource control. The user equipment may be in a radio resource control inactive mode or a radio resource control idle mode.

[0073] The centralized and distributed network nodes 112-120 of FIG. 1 may include, for example, base stations such as remote radio heads (RRHs), transmission reception points (TRPs), access points, node Bs (e.g., gNB) or other transmission sources. The centralized and distributed network nodes 112-120 may be configured to communicate with user equipment 110 via a network. The centralized and distributed network nodes 112-120 may be divided into centralized units and distributed units of a network node. For example, a network node may comprise a centralized network node 114 and multiple distributed network nodes, such as a distributed network node 112 and a distributed network node 116. In some embodiments, centralized network node 118 may include all layers. The centralized and distributed network nodes 112-120 may be logical entities comprising sets of cells (i.e., a matter of network configuration). Centralized network nodes 114 and 118 may include a radio resource control entity (e.g., a central unit control plane) which controls inter-centralized unit handover. Distributed network nodes 112, 116, and 120 may include a radio resource control entity (e.g., a local control plane) which controls intra-centralized unit handover (e.g., inter-distributed unit handover or intradistributed unit handover). A user equipment may connect and disconnect from centralized and distributed network nodes 112-120 via, for example, conditional handover.

[0074] FIG. 2 depicts an example apparatus 200 that may be configured to function as user equipment 110 or centralized and distributed network nodes 112-118. As shown in FIG. 2, the apparatus includes, is associated with, or is in communications with processing circuitry 220, a memory 240, and a communication interface 260. The processing circuitry 220 may be in communication with the memory device 240 via a bus for passing information among components of the apparatus. The memory device may be non-transitory and may include, for example, one or more volatile and / or non-volatile memories. In other words, for example, the memory device may be an electronic storage device (e.g., a computer readable storage medium)including gates configured to store data (e.g., bits) that may be retrievable by a machine (e.g., a computing device like the processing circuitry). The memory device may be configured to store information, data, content, applications, instructions, or the like for enabling the apparatus to carry out various functions in accordance with an example embodiment of the present disclosure. For example, the memory device could be configured to buffer input data for processing by the processing circuitry. Additionally or alternatively, the memory device could be configured to store instructions for execution by the processing circuitry.

[0075] The apparatus 200 may, in some embodiments, be embodied in various computing devices described as above. However, in some embodiments, the apparatus may be embodied as a chip or chip set. In other words, the apparatus may include one or more physical packages (e.g., chips) including materials, components and / or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and / or limitation of electrical interaction for component circuitry included thereon. The apparatus may therefore, in some cases, be configured to implement an embodiment on a single chip or as a single “system on a chip.” As such, in some cases, a chip or chipset may constitute means for performing one or more operations for providing the functionalities described herein.

[0076] The processing circuitry 220, also referenced as a processor, may be embodied in a number of different ways. For example, the processing circuitry may be embodied as one or more of various hardware processing means such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing element with or without an accompanying DSP, or various other circuitry including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like. As such, in some embodiments, the processing circuitry may include one or more processing cores configured to perform independently. A multi-core processing circuitry may enable multiprocessing within a single physical package. Additionally or alternatively, the processing circuitry may include one or more processors configured in tandem via the bus to enable independent execution of instructions, pipelining, and / or multithreading.

[0077] In an example embodiment, the processing circuitry 220 may be configured to execute instructions stored in the memory device 240 or otherwise accessible to the processing circuitry. Alternatively or additionally, the processing circuitry may be configured to execute hardcodedfunctionality. As such, whether configured by hardware or software methods, or by a combination thereof, the processing circuitry may represent an entity (e.g., physically embodied in circuitry) capable of performing operations according to an embodiment of the present disclosure while configured accordingly. Thus, for example, when the processing circuitry is embodied as an ASIC, FPGA or the like, the processing circuitry may be specifically configured hardware for conducting the operations described herein. Alternatively, as another example, when the processing circuitry is embodied as an executor of instructions, the instructions may specifically configure the processor to perform the algorithms and / or operations described herein when the instructions are executed. However, in some cases, the processing circuitry may be a processor of a specific device (e.g., an image or video processing system) configured to employ an embodiment by further configuration of the processing circuitry by instructions for performing the algorithms and / or operations described herein. The processing circuitry may include, among other things, a clock, an arithmetic logic unit (ALU) and logic gates configured to support operation of the processing circuitry.

[0078] The communication interface 260 may be any means such as a device or circuitry embodied in either hardware or a combination of hardware and software that is configured to receive and / or transmit data including media content in the form of video or image files, one or more audio tracks or the like. In this regard, the communication interface may include, for example, an antenna (or multiple antennas) and supporting hardware and / or software for enabling communications with a wireless communication network. Additionally or alternatively, the communication interface may include the circuitry for interacting with the antenna(s) to cause transmission of signals via the antenna(s) or to handle receipt of signals received via the antenna(s). In some environments, the communications interface may alternatively or also support wired communication. As such, for example, the communication interface may include a communication modem and / or other hardware / software for supporting communication via cable, digital subscriber line (DSL), universal serial bus (USB) or other mechanisms.

[0079] Turning now to FIG. 3, a signaling diagram for intra-centralized unit handover and intercentralized unit handover in a dual radio resource control scenario is provided in accordance with previous embodiments. A local control plane at distributed units 112 and 116 hosts an additional radio resource control entity for user equipment devices (e.g., user equipment 110) at the distributed network nodes 112 and 116 on top of an already existing radio resource control entityat the centralized unit control plane at the centralized units 114 and 118. The local control plane controls intra-centralized network node handover and the centralized unit control plane controls inter-centralized network node handover.

[0080] Functions of the local control plane include radio resource control handling for selected user equipment devices, forwarding of non-access stratum messages to the central unit control plane, and local mobility handling (e.g., conditional handover / layer 1 based mobility, interdistributed (or intra-centralized) unit handover, carrier aggregation, multi-transmission and reception point operation, discontinuous reception, in co-ordination with the central unit control plane).

[0081] Central unit control plane radio resource control functions include radio resource control state of the user equipment (radio resource control anchoring point never changes inside a network node), layer 3 handover requests, and all inter-centralized unit procedures (e.g., configuring and receiving measurements related to inter-centralized unit (114 / 118) handovers, inter-radio access technology handovers, dual connectivity, and the like.

[0082] Operations 302-320 illustrate an intra-centralized unit (112 / 116) handover. The user equipment 110 switches from distributed network node 112 to distributed network node 116.

[0083] At operation 302, centralized network node 114 sends a configuration to user equipment 110 where to report a measurement. Centralized network node 114 instructs the user equipment 110 to report measurements for inter-centralized unit (114 / 118) handover to centralized network node. In addition, centralized network node 114 instructs the user equipment 110 to report measurements for intra-centralized unit (112 / 116) handover to distributed network node 112.

[0084] At operation 304, user equipment transmits measurement reports to distributed network node 112. At this time, user equipment 110 is connected to distributed network node 112. User equipment 110 transmits measurements for intra-centralized unit (112 / 116) handover to the distributed network node 112.

[0085] At operation 306, distributed network node 112 identifies the best cell (116a) for user equipment 110. Distributed network node 112 identifies that the best cell (116a) is covered by distributed network node 116.

[0086] At operation 308, distributed network node 112 transmits a handover request to distributed network node 116.

[0087] At operation 310, distributed network node 116 transmits a handover response to distributed network node 112.

[0088] At operation 312, distributed network node 112 transmits, to the user equipment 110, a message including a radio resource control reconfiguration. The radio resource control reconfiguration is a signaling radio bearer (SRB) configuration. The radio resource control reconfiguration is provided by the local control plane.

[0089] At operation 314, distributed network node 112 notifies the centralized network node (114) of the intra-centralized unit (112 / 116) handover. The distributed network node 112 identifies the user equipment 110, the target distributed network node 116, and the target cell.

[0090] At operation 316, a random access channel procedure is performed between the user equipment 110 and the distributed network node 116. This establishes a connection between the user equipment 110 and the distributed network node 116.

[0091] At operation 318, the distributed network node 116 notifies the centralized network node 114 of the handover success. The distributed network node 116 is now connected to the user equipment 110.

[0092] At operation 320, the centralized network node 114 synchronizes the user equipment 110 state and context with the now serving distributed network node 116.

[0093] Operations 322-332 illustrate an inter-centralized unit (114 / 118) handover. The user equipment 110 switches from centralized network node 114 to centralized network node 118.

[0094] At operation 322, the user equipment 110 reports layer 3 measurements to centralized network node 114. The measurements are for inter-centralized unit (114 / 118) handover.

[0095] At operation 324, the centralized network node 114 identifies the best cell (414a) for user equipment 110. The best cell (414a) for user equipment 110 is covered by centralized network node 118.

[0096] At operation 326, centralized network node 114 transmits a handover request to centralized network node 118.

[0097] At operation 328, the centralized network node 118 transmits a handover response to centralized network node 114.

[0098] At operation 330, the centralized network node 114 transmits a radio resource control reconfiguration message to user equipment 110. The radio resource control is a data radio bearer configuration. The radio resource control reconfiguration is from a central unit control plane.

[0099] At operation 332, a random access channel procedure is performed between user equipment 110 and centralized network node 118. The user equipment 110 is handed over from the centralized network node 114 to the centralized network node 118.

[0100] Turning now to FIG. 4A, a signaling diagram illustrating simultaneous triggering of intracentralized unit (112 / 116) handover and inter-centralized unit (114 / 118) handover in a dual radio resource control scenario is provided in accordance with previous embodiments. Preparing two different handovers as illustrated in FIG. 4A is a waste of resources as only one of the handovers is required. The user equipment 110 of FIG. 4A does not trigger the two conflicting handovers as it only has one logical control plane entity and hence can only trigger one handover at a time. Instead, the user equipment 110 of FIG. 4A follows instructions from the network and is not aware that two handover preparations may be ongoing. The problem illustrated by FIG. 4A may apply to inter-distributed (or intra-centralized (112 / 116)) unit handover, and / or inter-centralized unit (114 / 118) handover.

[0101] At operation 402, the user equipment 110 transmits a measurement report to distributed network node 112. At this time, the user equipment is connected to distributed network node 112. The layer 1 measurement report is for supporting inter-distributed (or intra-centralized (112 / 116)) unit handover (layer 1 based handover) controlled by the local control plane at distributed network node 112.

[0102] At operation 404, the user equipment 110 transmits a measurement report to centralized network node 114. At this time, the user equipment is connected to centralized network node 114. The layer 3 measurement report is for supporting inter-centralized unit (114 / 118) handover (layer 3 based handover) controlled by the central unit control plane at centralized network node 114.

[0103] At operation 406, distributed network node 112 decides to initiate handover preparations. The distributed network node 112 transmits an inter-distributed (or intra-centralized (112 / 116)) unit handover request to distributed network node 116.

[0104] At operation 408, distributed network node 116 accepts the inter-distributed (or intra- centralized (112 / 116)) unit handover request. The distributed network node 116 transmits an inter-distributed (or intra-centralized (112 / 116)) unit handover response to distributed network node 112.

[0105] At operation 410, centralized network node 114 decides to initiate handover preparations. The centralized network node 114 transmits an inter-centralized unit (114 / 118) handover request to centralized network node 118.

[0106] At operation 412, centralized network node 118 accepts the inter-centralized unit (114 / 118) handover request. The centralized network node 118 transmits an inter-centralized unit (114 / 118) handover response to centralized network node 114.

[0107] Turning now to FIG. 4B, an illustration of inter-centralized unit (114 / 118) handover and intra-centralized unit (112 / 116) handover in a dual radio resource control scenario is provided in accordance with previous embodiments.

[0108] As illustrated in FIG. 4B, an intra-distributed unit handover 416a may be performed between, for example, cells 112a and 112b, both controlled by distributed network node 112. An intra-distributed unit handover 416a is controlled by the local control plane.

[0109] An inter-distributed unit (or intra-centralized (112 / 116)) handover 416b may be performed between, for example, cells 112a and 116a, controlled by distributed network nodes 112 and 116, respectively. An inter-distributed unit handover 416b is controlled by the local control plane. Both the intra-distributed unit handover 416a and the inter-distributed unit (i.e., cells 112a / l 16a) handover 416b are intra-centralized unit (112 / 116) handovers, with centralized network node 114 remaining connected to the user equipment 110.

[0110] An inter-centralized unit (114 / 118) handover 416c may be performed between, for example, cells 112a and 414a. Cell 112a is controlled by distributed unit 112 and centralized unit 114 and cell 414a is controlled by distributed network node 414 and centralized network node 118.

[0111] Turning now to FIG. 4C, a signaling diagram illustrating user equipment-triggered handover with the user equipment receiving two radio resource control reconfigurations is provided in accordance with previous embodiments. As shown in FIG. 4C, a local control plane and a centralized unit control plane decide in parallel to configure a conditional handover to the user equipment.

[0112] At operation 402, user equipment 110 transmits a measurement report for intra- centralized unit or inter-distributed unit (112 / 116) handover to distributed network node 112. Based on this measurement report, the local control plane decides to configure a conditional handover to the user equipment 110.

[0113] At operation 416, the distributed network node 112 transmits a radio resource control reconfiguration to the user equipment 110. The radio resource control reconfiguration is a conditional handover configuration from the local control plane.

[0114] At operation 404, the user equipment 110, before encountering the radio resource control reconfiguration received at operation 416, sends a measurement report to centralized network node 114. The measurement report is for inter-centralized unit (114 / 118) handover, and the central unit control plane decides on configuring a conditional handover to the user equipment 110.

[0115] At operation 418, the centralized network node 114 transmits a radio resource control reconfiguration to the user equipment 110. The radio resource control reconfiguration is a conditional handover configuration from the central unit control plane.

[0116] Turning now to FIG. 5A, a signaling diagram illustrating a user equipment adding a flag to a message to message to the distributed network node and the distributed network node reading the flag in accordance is provided with example embodiments of the present disclosure. In example embodiments, the methods performed in FIG. 5A avoid preparation for multiple handovers without sharing security keys between a distributed network node (112) and a centralized network node (114).

[0117] In one or more embodiments, at operation 502, the user equipment 110 transmits a message 502a to distributed network node 112. In some examples, the message 502a is a measurement report message 502a. In some examples, the measurement report message 502a may be provided for intra-centralized unit (112 / 116) conditional handover. For example, the measurement report message 502a may serve a local control plane handover.

[0118] In one or more embodiments, at operation 504, the user equipment 110 transmits a message 504a to a distributed network node 112. In some examples, the message 504a is a measurement report message 504a. In some examples, the measurement report message 504a may be provided for inter-centralized unit (114 / 118) handover. For example, the measurement report message 504a may serve a control unit control plane handover.

[0119] In one or more embodiments, the user equipment 110 adds a flag 504b to a message header of the measurement report message 504a. For example, the flag 504b may indicate that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. In some examples, a distributed unit 112 is able to read the flag 504b. In some examples, the flag 504bmay be a non-ciphered flag indicating that the message is to be inspected. In some cases, this flag can be configured or activated by a distributed network node 112 when a user equipment 110 reaches a distributed network node 112 border. In some cases, this flag 504b may be present whenever local control panel and centralized unit control panel mobility are running in parallel. In some examples, the flag 504b is received by the distributed network node 112. In some examples, the flag 504b indicates to the distributed network node 112 to check a packet of the measurement report message 504a (i.e., processing is triggered at the distributed network node 112. In some examples, the flag 504b can be realized as an additional field extending an existing radio resource control message header type. Alternatively, it can be realized by encapsulating the message (from the user equipment 110 to the centralized network node 114 or vice versa) as a message to distributed network node 112. In some examples, an encapsulated message has as one payload the flag 504b for distributed network node 112 and as a second payload the measurement report message 504a to be forwarded without further inspection by distributed network node 112.

[0120] In one or more embodiments, at operation 506, the distributed network node 112 reads the flag 504b. In some examples, the distributed network node determines, based on the flag, whether to transmit the message 504a to the centralized network node 114. For example, flag 504b may function similarly to a subject line of an email. For example, distributed network node 112 may read the flag 504b instead of the actual content of the message. In some examples, the distributed network node 112 identifies, based on the flag 504b, that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. The distributed network node 112 in some examples will determine not to forward the measurement report message 504a to a centralized network node 114 when the distributed unit previously received a measurement report message 502a for intra-centralized unit (112 / 116) handover (i.e., when an intra-centralized unit handover is ongoing). In some examples, this prevents another handover from being prepared by the centralized network node 114.

[0121] In one or more embodiments, at operation 508, the distributed network node 112 transmits an inter-distributed unit (i.e., intra-centralized unit) handover request to distributed network node 116. In some examples, the distributed network node 116 accepts the handover request.

[0122] In one or more embodiments, at operation 512, the distributed network node 116 transmits an inter-distributed unit (i.e., intra-centralized unit) handover response to the distributed network node 112. In some examples, the response indicates that the distributed network node 116 accepts the handover request.

[0123] In one or more embodiments, at operation 514, distributed network node 112 transmits a radio resource control reconfiguration message to user equipment 110. In some examples, the radio resource control reconfiguration is from the local control plane. In some examples, the user equipment 110 is handed over to distributed network node 116.

[0124] Turning now to FIG. 5B, a signaling diagram illustrating a distributed network node intercepting and reading a message from a user equipment is provided in accordance with example embodiments of the present disclosure. In this example, the user equipment 110 does not add a flag 504b to measurement report message 504a. Instead, various embodiments provide operation 516, where distributed network node 112 intercepts and reads measurement report message 504a. In some examples, the distributed network node 112 identifies that it is for intercentralized unit (114 / 118) handover. In some examples, distributed network node 112 determines not to forward measurement report message 504a to centralized network node 114 when the distributed unit previously received a measurement report message 502a for intra-centralized unit (112 / 116) handover. In some example embodiments, the local control plane has the ability to read messages sent between the user equipment 110 and the centralized unit 114. For example, security keys (e.g., ciphering keys for signaling radio bearer) may be shared between a distributed unit 112 and a centralized unit 114. As another example, message 504a may be integrity protected only but not ciphered (i.e., a ciphered checksum is used but the content is in clear text).

[0125] Turning now to FIG. 6A, a signaling diagram illustrating a distributed network node reading a flag from a user equipment after a handover is provided in accordance with example embodiments of the present disclosure. In some examples, FIG. 6A illustrates operations that may be performed without the sharing of security keys.

[0126] In one or more embodiments, at operation 502, the user equipment 110 transmits a message 502a to distributed network node 112. In some examples, the message 502a is a measurement report message 502a. In some examples, the measurement report message 502amay be provided for intra-centralized unit (112 / 116) handover. For example, the measurement report message 502a may serve a local control plane handover.

[0127] In one or more embodiments, at operation 602, based on measurement report message 502a, distributed network node 112 initiates an intra-centralized unit (112 / 116) handover (i.e., a local control plane handover). For example, distributed network node 112 may determine to initiate a handover to distributed network node 116. In some examples, distributed network node 112 begins handover preparation.

[0128] In one or more embodiments, at operation 504, the user equipment 110 transmits a message 504a to a distributed network node 112. In some examples, the message 504a is a measurement report message 504a. In some examples, the measurement report message 504a may be provided for inter-centralized unit (114 / 118) handover. For example, the measurement report message 504a may serve a control unit control plane handover.

[0129] In one or more embodiments, the user equipment 110 adds a flag 504b to the measurement report message 504a. For example, the flag 504b may indicate that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. In some examples, a distributed unit 112 is able to read the flag 504b. In some examples, the flag 504b may be a non-ciphered flag indicating that the message is to be inspected. In some cases, this flag can be configured or activated by a distributed network node 112 when a user equipment 110 reaches a distributed network node 112 border. In some cases, this flag 504b may be present whenever local control panel and centralized unit control panel mobility are running in parallel.

[0130] In one or more embodiments, at operation 506, the distributed network node 112 reads the flag 504b. In some examples, the distributed network node 112 identifies, based on the flag 504b, that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. The distributed network node 112 in some examples will determine not to forward the measurement report message 504a to a centralized network node 114 due to the intra-centralized unit (112 / 116) handover 602. In some examples, this prevents another handover from being prepared by the centralized network node 114.

[0131] In one or more embodiments, at operation 604, target cell preparation is performed. For example, a distributed network node 112 may prepare a target cell covered by distributed network node 116.

[0132] In one or more embodiments, at operation 514, distributed network node 112 transmits a radio resource control reconfiguration message to user equipment 110. In some examples, the radio resource control reconfiguration is from the local control plane. In some examples, the user equipment 110 is handed over to distributed network node 116.

[0133] Turning now to FIG. 6B, a signaling diagram illustrating a distributed network node intercepting and reading a message from a user equipment after a handover is provided in accordance with example embodiments of the present disclosure. In this example, the user equipment 110 does not add a flag 504b to measurement report message 504a. Instead, various embodiments provide operation 516, where distributed network node 112 intercepts and reads measurement report message 504a. In some examples, the distributed network node 112 identifies that it is for inter-centralized unit (114 / 118) handover. In some examples, distributed network node 112 determines not to forward measurement report message 504a to centralized network node 114 when the intra-centralized unit (112 / 116) handover decision 602 is ongoing. In some example embodiments, the local control plane has the ability to read messages sent between the user equipment 110 and the centralized unit 114. For example, security keys may be shared between a distributed unit 112 and a centralized unit 114.

[0134] Turning now to FIG. 7A, a signaling diagram illustrating a distributed network node enhancing and forwarding a message based on a received flag is provided in accordance with example embodiments of the present disclosure. In some examples, FIG. 7A illustrates operations that may be performed without the sharing of security keys.

[0135] In one or more embodiments, at operation 502, the user equipment 110 transmits a message 502a to distributed network node 112. In some examples, the message 502a is a measurement report message 502a. In some examples, the measurement report message 502a may be provided for intra-centralized unit (112 / 116) handover. For example, the measurement report message 502a may serve a local control plane handover.

[0136] In one or more embodiments, at operation 602, based on measurement report message 502a, distributed network node 112 initiates an intra-centralized unit (112 / 116) handover (i.e., a local control plane handover). For example, distributed network node 112 may determine to initiate a handover to distributed network node 116. In some examples, distributed network node 112 begins handover preparation.

[0137] In one or more embodiments, at operation 504, the user equipment 110 transmits a message 504a to a distributed network node 112. In some examples, the message 504a is a measurement report message 504a. In some examples, the measurement report message 504a may be provided for inter-centralized unit (114 / 118) handover. For example, the measurement report message 504a may serve a control unit control plane handover.

[0138] In one or more embodiments, the user equipment 110 adds a flag 504b to the measurement report message 504a. For example, the flag 504b may indicate that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. In some examples, a distributed unit 112 is able to read the flag 504b. In some examples, the flag 504b may be a non-ciphered flag indicating that the message is to be inspected. In some cases, this flag can be configured or activated by a distributed network node 112 when a user equipment 110 reaches a distributed network node 112 border. In some cases, this flag 504b may be present whenever local control panel and centralized unit control panel mobility are running in parallel.

[0139] In one or more embodiments, at operation 506, the distributed network node 112 reads the flag 504b. In some examples, the distributed network node 112 identifies, based on the flag 504b, that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. The distributed network node 112 in some examples will enhance 702 the message with a flag 706 that indicates that intra-centralized unit (112 / 116) handover preparation is ongoing.

[0140] In one or more embodiments, at operation 704, the distributed network node 12 transmits the measurement report message 504a to the centralized network node 114. In some examples, the measurement report message 504a is enhanced 702 with a flag 706 indicating that intracentralized unit (112 / 116) handover preparation is ongoing (i.e., that local control plane handover is ongoing).

[0141] In one or more embodiments, at operation 604, target cell preparation is performed. For example, a distributed network node 112 may prepare a target cell covered by distributed network node 116.

[0142] In one or more embodiments, at operation 708, the centralized network node 114 determines not to initiate inter-centralized network node handover preparation. In some examples, the centralized network node 114 initiates this determination based on reading flag 706 on measurement report 504a. In other examples, centralized network node 114 may determine to interrupt intra-centralized unit (112 / 116) handover preparation and initiate inter-centralized unit preparation. In some examples, resources are saved by preventing preparation for multiple handovers simultaneously.

[0143] In one or more embodiments, at operation 514, distributed network node 112 transmits a radio resource control reconfiguration message to user equipment 110. In some examples, the radio resource control reconfiguration is from the local control plane. In some examples, the user equipment 110 is handed over to distributed network node 116.

[0144] Turning now to FIG. 7B, a signaling diagram illustrating a distributed network node enhancing and forwarding a message based on intercepting and reading a message is provided in accordance with example embodiments of the present disclosure. In this example, the user equipment 110 does not add a flag 504b to measurement report message 504a. Instead, various embodiments provide operation 516, where distributed network node 112 intercepts and reads measurement report message 504a. In some examples, the distributed network node 112 identifies that it is for inter-centralized unit (114 / 118) handover. In some examples, distributed network node 112 enhances 702 the measurement report message 504a with a flag 706 indicating that intra-centralized unit preparation is ongoing. In some embodiments, the distributed network node 112 forwards the measurement report message 504a with the flag 706 to the centralized network node 114 at operation 704. In some example embodiments, the local control plane has the ability to read messages sent between the user equipment 110 and the centralized unit 114. For example, security keys may be shared between a distributed unit 112 and a centralized unit 114.

[0145] Turning now to FIG. 8A, a signaling diagram illustrating a distributed network node reading a flag from a user equipment when there is no ongoing intra-centralized unit (112 / 116) handover is provided in accordance with example embodiments of the present disclosure. In some examples, FIG. 8A illustrates operations that may be performed without the sharing of security keys.

[0146] In one or more embodiments, at operation 504, the user equipment 110 transmits a message 504a to a distributed network node 112. In some examples, the message 504a is a measurement report message 504a. In some examples, the measurement report message 504a may be provided for inter-centralized unit (114 / 118) handover. For example, the measurement report message 504a may serve a control unit control plane handover.

[0147] In one or more embodiments, the user equipment 110 adds a flag 504b to the measurement report message 504a. For example, the flag 504b may indicate that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. In some examples, a distributed unit 112 is able to read the flag 504b.

[0148] In one or more embodiments, at operation 506, the distributed network node 112 reads the flag 504b. In some examples, the distributed network node 112 identifies, based on the flag 504b, that the measurement report message 504a is for inter-centralized unit (114 / 118) handover. In some examples, distributed network node 112 determines that there is no ongoing intracentralized unit (112 / 116) handover preparation ongoing. In some examples, the distributed network node 112 determines that the measurement report message 504a can be forwarded to centralized network node 114.

[0149] In one or more embodiments, at operation 704, the distributed network node 112 transmits the measurement report message 504a to the centralized network node 114. For example, the distributed network node 112 may transmit the message 504a to the centralized network node 114 when an intra-centralized handover is not ongoing and the message 504a includes the flag 504b. In some examples, this serves an inter-centralized unit (114 / 118) handover to the centralized network node 114.

[0150] In one or more embodiments, at operation 802, the user equipment 110 transmits, and the distributed network node 112 receives, a measurement report message 802a to distributed network node 112. In some examples, the measurement report message 802a indicates intracentralized unit (112 / 116) handover (i.e., the measurement report message 802a may serve an intra-centralized unit (112 / 116) handover).

[0151] In one or more embodiments, at operation 804, the distributed network node 112 ignores the measurement report message 802a received from the user equipment 110. In some examples, the distributed network node 112 ignores the measurement report message 802a because it previously forwarded the measurement report message 504a indicating inter-centralized unit (114 / 118) handover. In some examples, the distributed network node 112 determines that the inter-centralized unit (114 / 118) handover is ongoing based on the measurement report message 802a.

[0152] In one or more embodiments, at operation 806, the centralized network node 114 transmits an inter-centralized unit (114 / 118) handover request to centralized network node 118.In some embodiments, the centralized network node 114 transmits the request in response to receiving the measurement report message at operation 704. In some examples, centralized network node 118 determines to accept the request.

[0153] In one or more embodiments, at operation 808, the centralized network node 118 transmits an inter-centralized handover response to centralized network node 114. In some examples, centralized network node 118 communicates that the inter-centralized unit (114 / 118) handover request is accepted.

[0154] In one or more embodiments, at operation 812, the centralized network node 114 transmits, to the user equipment 110, a radio resource control reconfiguration. In some examples, the radio resource control reconfiguration is from a centralized unit control plane. In some examples, the user equipment 110 is handed over to centralized unit 118.

[0155] Turning now to FIG. 8B, a signaling diagram illustrating a distributed network node intercepting and reading a message from a user equipment when there is no ongoing intracentralized unit (112 / 116) handover is provided in accordance with example embodiments of the present disclosure. In this example, the user equipment 110 does not add a flag 504b to measurement report message 504a. Instead, various embodiments provide operation 516, where distributed network node 112 intercepts and reads measurement report message 504a. In some examples, the distributed network node 112 identifies that it is for inter-centralized unit (114 / 118) handover. In some examples, distributed network node 112 forwards the measurement report message 504a with the flag 706 to the centralized network node 114 at operation 704. In some example embodiments, the local control plane has the ability to read messages sent between the user equipment 110 and the centralized unit 114. For example, security keys may be shared between a distributed unit 112 and a centralized unit 114.

[0156] Turning now to FIG. 9A, a signaling diagram illustrating a distributed network node reading a flag from a centralized unit is provided in accordance with example embodiments of the present disclosure. In some examples, FIG. 9A illustrates operations that may be performed without the sharing of security keys.

[0157] In one or more embodiments, at operation 902, a user equipment 110 transmits a first measurement report to centralized network node 114. In some examples, the first measurement report indicates inter-centralized unit (114 / 118) handover.

[0158] In one or more embodiments, at operation 904, the centralized network node 114 initiates a handover. In some examples, the centralized network node 114 initiates the handover based on the measurement report 902. In some examples, the centralized network node 114 determines to hand over the user equipment 110 to centralized network node 118.

[0159] In one or more embodiments, at operation 906, the user equipment 110 transmits a second measurement report to distributed network node 112. In some examples, the second measurement report indicates intra-centralized unit (112 / 116) handover.

[0160] In one or more embodiments, at operation 908, target cell preparation is performed. For example, a centralized network node 114 may prepare a target cell covered by centralized network node 118.

[0161] In one or more embodiments, at operation 912, centralized network node 114 transmits a centralized unit control plane radio resource control reconfiguration message 912a. In some examples, the centralized network node 114 intends for the centralized unit control plane radio resource control reconfiguration message 912a for the user equipment 110. In some examples, the centralized network node 114 adds a flag 912b indicating that it is intended for intercentralized unit (114 / 118) handover. In some examples, the centralized unit control plane radio resource control reconfiguration message 912a is intercepted by the distributed network node 112. In some examples, the distributed network node 112 reads the flag 912b and determines that the centralized unit control plane radio resource control reconfiguration message 912a should be forwarded to the user equipment. In some examples, the flag 912b may be a non-ciphered flag indicating that the message is to be inspected. In some cases, this flag can be configured or activated by a distributed network node 112 when a user equipment 110 reaches a distributed network node 112 border. In some cases, this flag 912b may be present whenever local control panel and centralized unit control panel mobility are running in parallel.

[0162] In one or more embodiments, at operation 914, the distributed network node 112 forwards the centralized control plane radio resource control reconfiguration message 912a to the user equipment 110. In some examples, the distributed network node 112 forwards the centralized control plane radio resource control reconfiguration message 912a based on the flag 912b. In some examples, after distributed unit 112 reads message 912a, it initiates a distributed unit-internal prohibit timer. In some examples, the prohibit timer may be dimensioned to the duration of a typical inter-centralized unit (114 / 118) handover, such as 80msec. In someexamples, until the prohibit timer is expired, the distributed unit 112 does not issues intracentralized unit (112 / 116) handover commands to the user equipment 110.

[0163] In one or more embodiments, at operation 916, the distributed network node 112 determines, based on the flag 912b, not to issue a handover command in spite of the second measurement report message received at operation 906. For example, the distributed network node 112 may determine not to issue a handover command because an inter-centralized unit (114 / 118) handover was initiated at operation 904.

[0164] Turning now to FIG. 9B, a signaling diagram illustrating a distributed network node intercepting and reading a message from a centralized unit is provided in accordance with example embodiments of the present disclosure. In this example, the centralized network node 114 does not add a flag 912b to message 912a. Instead, in various embodiments, distributed network node 112 intercepts and reads the centralized unit control plane radio resource control reconfiguration message 912a. In some examples, the distributed network node 112 identifies that centralized unit control plane radio resource control reconfiguration message 912a is for inter-centralized unit (114 / 118) handover. In some examples, distributed network node 112 forwards the centralized unit control plane radio resource control reconfiguration message 912a with the flag 912b to the user equipment 110 at operation 914. In some examples, at operation 918, the distributed network node 112 determines not to issue the local control plane handover command based on the centralized unit control plane radio resource control reconfiguration. In some example embodiments, the local control plane has the ability to read messages sent between the user equipment 110 and the centralized unit 114. For example, security keys may be shared between a distributed unit 112 and a centralized unit 114.

[0165] Turning now to FIG. 10, a flowchart is provided illustrating processes performed by a user equipment, a distributed network node, and a centralized network node to prepare for intercentralized unit (114 / 118) handover or intra-centralized unit (112 / 116) handover in accordance with example embodiments of the present disclosure.

[0166] In one or more embodiments, user equipment 110 generates a measurement report message 504a. For example, the measurement report message 504a may indicate intracentralized unit (112 / 116) handover or inter-centralized unit (114 / 118) handover. In some examples, the measurement report message may have a flag 504b attached indicating whether the message 504a is intended for a centralized unit 114.

[0167] In one or more embodiments, at operation 1001, the measurement report message 504a is received by the distributed network node 112. In some examples, at operation 1001, the distributed network node 112 determines whether the measurement report message is for intracentralized unit (112 / 116) handover. In some examples, the distributed network node 112 determines whether the measurement report message 504a indicates a local control plane handover.

[0168] In example situations where the measurement report message 504a is for intra-centralized unit (112 / 116) handover, distributed network node 112 determines, at operation 1002, whether a centralized unit control plane handover is on-going (i.e., whether an inter-centralized unit (114 / 118) handover is ongoing). In example situations where a centralized unit control plane handover is not ongoing, the distributed network node 112 prepares target cells for intracentralized unit (112 / 116) handover at operation 1006. In example situations where a centralized unit control plane handover is ongoing, the distributed network node 112 will ignore the measurement report message 504a at operation 1004 in order to save network resources.

[0169] In example situations where the measurement report message 504a is for inter-centralized unit (114 / 118) handover, distributed network node 112 determines, at operation 602, whether an intra-centralized unit (112 / 116) handover is ongoing (i.e., whether a local control plane handover is ongoing). In examples where an intra-centralized unit (112 / 116) handover is not ongoing, the distributed network node forwards the message 504a to the centralized network node 114 at operation 704.

[0170] In example situations where an intra-centralized unit (112 / 116) handover is ongoing, the distributed network node 112 determines, at operation 1003, whether it can enhance 702 the measurement report message 504a to indicate that an intra-centralized unit (112 / 116) handover is ongoing. In example situations where the distributed network node 112 cannot enhance 702 the message 594a, the distributed network node 112 determines not to forward the measurement report message 504a to the centralized unit 114 at operation 1004. In examples where the distributed network node 112 can enhance 702, the measurement report message 504a, it proceeds to enhance the message 504a at operation 702. In some examples, the distributed network node 112 then forwards the message 504a to the centralized network node 114 at operation 704.

[0171] In one or more embodiments, at operation 1014, the centralized network node 114 determines whether the received measurement report message 504a is enhanced. In examples where the measurement report message 504a is not enhanced, the centralized network node 114 prepares target cells for inter-centralized unit (114 / 118) handover at operation 1009.

[0172] In one or more embodiments where the message 504a is enhanced, at operation 708, the centralized network node 114 determines whether a centralized unit control plane handover would be better than a local control plane handover (i.e., whether an inter-centralized unit (114 / 118) handover would be better than an intra-centralized unit (112 / 116) handover). In example situations where an inter-centralized unit (114 / 118) handover would not be better than an intra-centralized unit (112 / 116) handover, the centralized network node 114 determines not to prepare target cells at operation 1012. In example situations where the inter-centralized unit (114 / 118) handover would be better than an intra-centralized unit (112 / 116) handover, the centralized network node 114 interrupts distributed network node 112 from preparing target cells at operation 1008. In some examples, the centralized network node then prepares target cells for inter-centralized handover at operation 1009.

[0173] Turning now to FIG. 11, a signaling diagram illustrating a centralized network node preparing conditional handover configurations and a distributed network node avoiding preparation for conditional handover is provided in accordance with example embodiments of the present disclosure.

[0174] In one or more embodiments, at operation 1102, a centralized network node 114 transmits, during a user equipment 110 context request-response 1104 and to a distributed network node 112, a list of cell identifiers 1106 that are in the border of a distributed network node 112 serving area (113). In alternative examples, the centralized network node 114 may transmit cell identifiers that are not part of the current distributed network node 112 serving area (113). In some examples, this allows the distributed unit 112 to determine that a cell is a border area cell.

[0175] In one or more embodiments, at operation 1108, the user equipment 110 transmits, to the distributed network node 112, a measurement report message 1108a. In some examples, the measurement report message contains inter-centralized unit measurements and intra-centralized unit measurements (i.e., inter-distributed unit measurements and intra-distributed unit measurements).

[0176] In one or more embodiments, at operation 1112, the distributed network node 112 identifies, based on the measurement report message 1108a and the list of cell identifiers 1106, that the user equipment 110 is at the area border of the distributed network node 112. In some examples, the distributed network node 112 knows that the user equipment 110 is at the area border based on the measurement report message 1108a containing both inter-centralized unit measurements and intra-centralized unit measurements.

[0177] In one or more embodiments, at operation 1114, the distributed network node 112 forwards the message 1108a to the centralized network node 114 for the conditional handover preparation.

[0178] In one or more embodiments, at operation 1115, the centralized network node 114 prepares target cells for conditional handover. In one or more embodiments, the centralized network node 114 generates a radio resource control configuration command 912a for the conditional handover. In example conditional handover scenarios, including lower layer triggered mobility, target cells are prepared in advance.

[0179] In one or more embodiments, at operation 912, centralized network node 114 transmits a centralized unit control plane radio resource control reconfiguration message 912a. In some examples, the centralized network node 114 intends for the centralized unit control plane radio resource control reconfiguration message 912a for the user equipment 110. In some examples, the centralized network node 114 adds a flag 912b indicating that it is intended for intercentralized unit (114 / 118) handover. In some situations, the flag 912b indicates that the message (i.e., command) 912a is for inter-centralized unit (114 / 118) conditional handover. In some examples, the centralized unit control plane radio resource control reconfiguration message 912a is intercepted by the distributed network node 112.

[0180] In one or more embodiments, at operation 506, the distributed network node 112 reads the flag 912b and determines that the centralized unit control plane radio resource control reconfiguration message 912a should be forwarded to the user equipment. In some examples, the distributed network node 112 determines that the message 912a should be forwarded to the user equipment because the flag 912b indicates conditional handover for user equipment 110. In some examples, the distributed network node 112 indicates that the flag 912b indicates intercentralized unit (114 / 118) conditional handover.

[0181] In one or more embodiments, at operation 914, the distributed network node 112 forwards the message 912a to the user equipment 110. In some examples, the message 912a is a command to the user equipment including a conditional handover configuration from a central unit control plane.

[0182] In one or more embodiments, at operation 802, the user equipment 110 transmits, to the distributed network node 112, a measurement report message 802a. In one or more embodiments, the measurement report message 802a contains intra-centralized unit measurements (i.e., for intra-centralized unit (112 / 116) conditional handover).

[0183] In one or more embodiments, at operation 1116, the distributed network node 112 ignores the measurement report message 802a received from the user equipment 110. In some examples, the distributed network node 112 ignores the measurement report message 802a based on previously identifying that flag 912b indicated inter-centralized unit (114 / 118) conditional handover.

[0184] Turning now to FIG. 12, a signaling diagram illustrating a centralized network node preparing conditional handover configurations and a user equipment avoiding reporting intra- centralized network node measurements is provided in accordance with example embodiments of the present disclosure.

[0185] In one or more embodiments, at operation 1102, a centralized network node 114 transmits, during a user equipment 110 context request-response 1104, a list of cell identifiers 1106 that are in the border of a distributed network node 112 serving area (113). In alternative examples, the centralized network node 114 may transmit cell identifiers that are not part of the current distributed network node 112 serving area (113). In some examples, this allows the distributed unit 112 to determine that a cell is a border area cell.

[0186] In one or more embodiments, at operation 1108, the user equipment 110 transmits, to the distributed network node 112, a measurement report message 1108a. In some examples, the measurement report message contains inter-centralized unit measurements and intra-centralized unit measurements (i.e., inter-distributed unit measurements and intra-distributed unit measurements).

[0187] In one or more embodiments, at operation 1112, the distributed network node 112 identifies, based on the measurement report message 1108a and the list of cell identifiers 1106, that the user equipment 110 is at the area border of the distributed network node 112. In someexamples, the distributed network node 112 knows that the user equipment 110 is at the area border based on the measurement report message 1108a containing both inter-centralized unit measurements and intra-centralized unit measurements.

[0188] In one or more embodiments, at operation 1114, the distributed network node 112 forwards the message 1108a to the centralized network node 114.

[0189] In one or more embodiments, at operation 1115, the centralized network node 114 prepares target cells for conditional handover. In one or more embodiments, the centralized network node 114 generates a radio resource control configuration command 912a for the conditional handover. In example conditional handover scenarios, including lower layer triggered mobility, target cells are prepared in advance.

[0190] In one or more embodiments, at operation 912, centralized network node 114 transmits a centralized unit control plane radio resource control reconfiguration message 912a. In some examples, the centralized network node 114 intends for the centralized unit control plane radio resource control reconfiguration message 912a for the user equipment 110. In some examples, the centralized network node 114 adds a flag 912b indicating that it is intended for intercentralized unit (114 / 118) handover. In some situations, the flag 912b indicates that the message (i.e., command) 912a is for inter-centralized unit (114 / 118) conditional handover. In some examples, the centralized unit control plane radio resource control reconfiguration message 912a is intercepted by the distributed network node 112.

[0191] In one or more embodiments, at operation 506, the distributed network node 112 reads the flag 912b and determines that the centralized unit control plane radio resource control reconfiguration message 912a should be forwarded to the user equipment. In some examples, the distributed network node 112 determines that the message 912a should be forwarded to the user equipment because the flag 912b indicates conditional handover for user equipment 110. In some examples, the distributed network node 112 indicates that the flag 912b indicates intercentralized unit (114 / 118) conditional handover.

[0192] In one or more embodiments, at operation 914, the distributed network node 112 forwards the message 912a to the user equipment 110. In some examples, the message 912a is a command to the user equipment including a conditional handover configuration from a central unit control plane.

[0193] In one or more embodiments, at operation 1202, the user equipment 110 avoids reporting intra-centralized network node measurements to the distributed network node 112. In some examples, the user equipment 110 avoids reporting intra-centralized network node measurements due to the radio resource control reconfiguration message 912a, which indicates inter-centralized network node conditional handover. In some examples, this prevents multiple handover configurations from being prepared at the same time unnecessarily.

[0194] Turning now to FIG. 13, a signaling diagram illustrating a distributed network node instructing a user equipment to report only to a centralized network node is provided in accordance with example embodiments of the present disclosure.

[0195] In one or more embodiments, at operation 1102, a centralized network node 114 transmits, during a user equipment 110 context request-response 1104, a list of cell identifiers 1106 that are in the border of a distributed network node 112 serving area (113). In alternative examples, the centralized network node 114 may transmit cell identifiers that are not part of the current distributed network node 112 serving area (113). In some examples, this allows the distributed unit 112 to determine that a cell is a border area cell.

[0196] In one or more embodiments, at operation 1108, the user equipment 110 transmits, to the distributed network node 112, a measurement report message 1108a. In some examples, the measurement report message contains inter-centralized unit measurements and intra-centralized unit measurements (i.e., inter-distributed unit measurements and intra-distributed unit measurements).

[0197] In one or more embodiments, at operation 1112, the distributed network node 112 identifies, based on the measurement report message 1108a and the list of cell identifiers 1106, that the user equipment 110 is at the area border of the distributed network node 112. In some examples, the distributed network node 112 knows that the user equipment 110 is at the area border based on the measurement report message 1108a containing both inter-centralized unit measurements and intra-centralized unit measurements.

[0198] In one or more embodiments, at operation 1302, the distributed network node 112 transmits, to the user equipment 110, an instruction 1302a to report only to a local control plane or a central unit control plane. For example, if the instruction 1302a indicates that the user equipment 110 should only report to a local control plane, the user equipment 110 will only report to distributed network node 112. As another example, if the instruction 1302 indicates thatthe user equipment 110 should only report to a centralized control unit, the user equipment 110 will only report to centralized network node 114. In some examples, the instruction 1302a is based on whether the user equipment 110 is at the border area. For example, when the user equipment 110 is at the border area, the distributed network node transmits the instruction 1302a to transmit only to the centralized network node 114. As another example, when the user equipment 110 is not at the border area, the distributed network node 112 transmits the instruction 1302a to report only to the distributed network node 112.

[0199] In one or more embodiments, at operation 1304, the user equipment 110 transmits, to the centralized network node 114, a measurement report 1304a. In some examples, the measurement report 1304a contains both inter-centralized unit measurements and intra-centralized unit measurements (i.e., inter-distributed unit measurements and intra-distributed unit measurements).

[0200] In one or more embodiments, at operation 1306, the centralized network node 114 handles any handovers involving the user equipment 110. In some embodiments, the centralized network node 114 handles user equipment 110 handovers based on the measurement report message 1304a. In some examples, the centralized network node 114 may handle an intercentralized unit (114 / 118) handover. In other examples, the centralized network node 114 may handle an intra-centralized unit (112 / 116) handover (i.e., an intra-distributed unit handover or an inter-distributed unit handover).

[0201] In some examples, the distributed network node 112 may receive a second measurement report message from user equipment 110 (i.e., if the instruction 1302a indicates that the user equipment 110 should report to the distributed network node). In these examples, the distributed network node 112 may initiate an intra-centralized unit (112 / 116) conditional handover preparation based on the second measurement report message.

[0202] Turning now to FIG. 14, a flowchart illustrating processes performed by a user equipment, a distributed network node, and a centralized network node when a user equipment is at a border area of the distributed network node is provided in accordance with example embodiments of the present disclosure.

[0203] In one or more embodiments, user equipment 110 generates a measurement report message 504a. For example, the measurement report message 504a may indicate intra- centralized unit (112 / 116) handover and / or inter-centralized unit (114 / 118) handover. In someexamples, the measurement report message may have a flag 504b attached indicating whether the message 504a is intended for a centralized unit 114.

[0204] In one or more embodiments, at operation 1112, the distributed network node 112 determines whether the user equipment 110 is at a border area served by distributed unit 112. For example, the distributed network node 112 may determine that the user equipment 110 is at a border area served by distributed network node 112 based on whether the measurement report message 504a contains both intra-centralized unit measurements and inter-centralized unit measurements. In example situations where the user equipment 110 is not at a border area of distributed network node 112, the distributed network node 112 performs normal operations at operation 1406.

[0205] In example situations where the distributed network node 112 determines that the user equipment 110 is at the border area of distributed network node 112, the distributed network node 112 determines, at operation 1402, whether a centralized unit control plane has already prepared target cells. In some examples, this indicates whether an inter-centralized unit (114 / 118) conditional handover is ongoing. In example situations where the centralized unit control plane has prepared target cells, the distribute network node 112 ignores the message 504a at operation 1404. In example situations where the centralized unit control plane has not prepared target cells, the distributed network node 112 forwards the measurement report message 504a to the centralized network node 114 at operation 1114. In example embodiments, the centralized network node 114 then prepares cells for conditional handover at operation 1306.

[0206] Turning now to FIG. 15, a signaling diagram illustrating a distributed network node comparing signal levels of intra-centralized unit (112 / 116) cells and inter-centralized unit (114 / 118) cells is provided in accordance with example embodiments of the present disclosure.

[0207] In one or more embodiments, at operation 502, user equipment 110 transmits, to the distributed network node 112, a measurement report message 502a. In some examples, the measurement report message 502a indicates intra-centralized unit (112 / 116) conditional handover. In some examples, the measurement report message 502a is intended for distributed network node 112. For example, the measurement report message may be intended for a local control plane.

[0208] In one or more embodiments, at operation 602, the distributed network node 112 initiates an intra-centralized unit (112 / 116) handover. In some examples, the distributed network node112 prepares cells for intra-centralized unit (112 / 116) conditional handover. In some examples, the distributed network node 112 generates a radio resource control configuration for intracentralized unit (112 / 116) conditional handover.

[0209] In one or more embodiments, at operation 514, the distributed network node 112 transmits a radio resource control reconfiguration message to user equipment 110. For example, the radio resource control reconfiguration message may contain a conditional handover configuration from the local control plane (i.e., an intra-centralized unit (112 / 116) conditional handover configuration).

[0210] In one or more embodiments, at operation 1502, the user equipment 110 transmits a measurement report message 1502a to the distributed network node 112. For example, the measurement report message 1502a may indicate inter-centralized unit (114 / 118) handover. For example, the measurement report message 1502a may be intended for a centralized network node 114.

[0211] In one or more embodiments, at operation 1504, the distributed network node 112 inspects the measurement report message 1502a to determine the signal levels of intra- centralized unit (112 / 116) cells and inter-centralized unit (114 / 118) cells. In some examples, the distributed network node 112 compares the intra-centralized unit cell measurements from measurement report message 502a with the inter-centralized unit cell measurements from measurement report message 1502a. In some examples, if the intra-centralized unit measurements have better signal levels than the inter-centralized unit measurements, the distributed network node 112 will determine not to forward the measurement report message 1502 to the centralized network node 114. In some examples, if the inter-centralized unit measurements have better signal levels than the intra-centralized unit measurements, the distributed network node 112 will determine to forward the measurement report message 1502a to the centralized network node 114.

[0212] In some examples, the measurement report message 1502a is intended for centralized network node 114 but sent as a message to be forwarded by distributed network node 112. In these examples, the user equipment 110 uses security settings in place for distributed network node 112.

[0213] In one or more embodiments, at operation 1506, the distributed network node 112 forwards the measurement report message 1502a to the centralized network node 114. Forexample, the distributed network node 112 may forward the measurement report message 1502a to the centralized network node 114 when the inter-centralized unit (114 / 118) cells have better signal levels than the intra-centralized unit (112 / 116) cells.

[0214] In one or more embodiments, at operation 1115, the centralized network node 114 prepares target cells for conditional handover. In one or more embodiments, the centralized network node 114 generates a radio resource control reconfiguration message 812 for a user equipment 110. In some examples, a central unit control plane generates the radio resource control reconfiguration message 812. In example conditional handover scenarios, including lower layer triggered mobility, target cells are prepared in advance.

[0215] In one or more embodiments, at operation 812, the centralized network node 114 transmits, to the user equipment 110, a radio resource control reconfiguration message 812. In some examples, the radio resource control reconfiguration message 812 is a conditional handover configuration. In some examples, the radio resource control reconfiguration message 812 is from the central unit control plane.

[0216] Turning now to FIG. 16, a signaling diagram illustrating a user equipment modifying intra-centralized unit (112 / 116) conditional handover execution conditions is provided in accordance with example embodiments of the present disclosure.

[0217] In one or more embodiments, at operation 1602, the centralized network node 114 transmits, to the user equipment 110, a configuration 1602a for local control plane conditional handover modification (i.e., intra-centralized unit (112 / 116) conditional handover modification). For example, the centralized network node 114 may determine and transmit a configuration 1602a that describes conditions for modifying intra-centralized unit (112 / 116) conditional handover execution conditions (i.e., local control plane conditional handover execution conditions). In some examples, the modification will be an increase in intra-centralized unit (112 / 116) conditional handover A3 offset. In some examples, this results in a gradual prioritization of inter-centralized unit (114 / 118) conditional handover over intra-centralized unit (112 / 116) conditional handover.

[0218] In one or more embodiments, at operation 502, user equipment 110 transmits, to the distributed network node 112, a measurement report message 502a. In some examples, the measurement report message 502a indicates intra-centralized unit (112 / 116) conditional handover. In some examples, the measurement report message 502a is intended for distributednetwork node 112. For example, the measurement report message may be intended for a local control plane.

[0219] In one or more embodiments, at operation 514, the distributed network node 112 transmits a radio resource control reconfiguration message to user equipment 110. For example, the radio resource control reconfiguration message may contain a conditional handover configuration from the local control plane (i.e., an intra-centralized unit (112 / 116) conditional handover configuration).

[0220] In or more embodiments, at operation 1604, the user equipment 110 transmits, to the distributed network node 112, a message confirming that radio resource control reconfiguration is complete. For example, the message may confirm that the user equipment is configured with a local control plane conditional handover configuration (i.e., intra-centralized unit (112 / 116) conditional handover configuration).

[0221] In one or more embodiments, at operation 1606, the user equipment 110 determines that conditions for modifying intra-centralized unit (112 / 116) conditional handover execution conditions are met. For example, the user equipment 110 may determine that conditions received as part of configuration 1602a are met for modifying intra-centralized unit (112 / 116) conditional handover modification. In one or more embodiments, user equipment 110 modifies an intra- centralized unit (112 / 116) conditional handover execution condition based on the conditions being met.

[0222] In one or more embodiments, at operation 1608, a user equipment 110 evaluates execution conditions for intra-centralized conditional handover. In one or more embodiments, the execution conditions being modified are new based on the modification made at operation 1606.

[0223] Turning now to FIG. 17, a flowchart illustrating processes performed by a user equipment, a distributed network node, and a centralized network node when the distributed unit compares intra-centralized unit cell quality and inter-centralized unit cell quality is provided in accordance with example embodiments of the present disclosure.

[0224] In one or more embodiments, user equipment 110 generates a measurement report message 504a. For example, the measurement report message 504a may indicate intra- centralized unit (112 / 116) handover and / or inter-centralized unit (114 / 118) handover. In someexamples, the user equipment 110 transmits the measurement report message 504a to the distributed network node 112.

[0225] In one or more embodiments, at operation 1504, the distributed network node 112 determines, based on the measurement report message 504a, whether intra- centralized unit cells have a better signal quality than inter-centralized unit (114 / 118) cells. In example situations where the intra-centralized unit (112 / 116) cells have a better signal quality than the intercentralized unit (114 / 118) cells, the distributed network node 112 does not forward the measurement report message 504a to the centralized unit at operation 1702. In example situations where the inter-centralized unit (114 / 118) cells have a better signal quality than the inter-centralized unit (114 / 118) cells, the distributed network node 112 forwards the message 504a to the centralized network node 114 at operation 1506. In some examples, the centralized network node 114 then prepares target cells for conditional handover at operation 1306.

[0226] In one or more embodiments, at operation 1602, the centralized network node 114 transmits, to the user equipment 110, a configuration 1602a for local control plane conditional handover modification (i.e., intra-centralized unit (112 / 116) conditional handover modification). For example, the configuration 1602a may describe conditions for modifying intra-centralized unit (112 / 116) conditional handover execution conditions (i.e., local control plane conditional handover execution conditions).

[0227] In one or more embodiments, at operation 1702, the user equipment 110 determines whether an intra-centralized unit (112 / 116) conditional handover configuration (i.e., local control plane conditional handover configuration) exists for the user equipment 110. In example situations where an intra-centralized unit (112 / 116) conditional handover configuration does not exists, the user equipment evaluates an inter-centralized unit (114 / 118) conditional handover configuration (i.e., centralized control plane conditional handover configuration) at operation 1704.

[0228] In example embodiments where an intra-centralized unit (112 / 116) conditional handover configuration exists for the user equipment 110 the user equipment 110 evaluates whether a condition for intra-centralized unit (112 / 116) conditional handover modification is met at operation 1606. For example, the condition for intra-centralized unit (112 / 116) conditional handover modification may be received as part of configuration 1602a. In example embodiments where the condition is met, the user equipment further modifies the intra-centralized unit(112 / 116) conditional handover execution condition at operation 1606. In example embodiments where the condition is not met, the user equipment evaluates both the intra-centralized unit (112 / 116) conditional handover configuration and an inter-centralized unit (114 / 118) conditional handover configuration.

[0229] Turning now to FIG. 18, an example flowchart is illustrated for a process 1800 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to determine whether to forward a message to one of a user equipment (110) or a centralized network node (114).

[0230] As shown in block 1802 of FIG. 18, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for inter-centralized unit (114 / 118) handover. In one or more embodiments, when the distributed network node (112) receives (504) the message from the user equipment (110), the message comprises a measurement report message (504a) and the flag (504b) further indicates that the message is directed to the centralized network node (114). In one or more embodiments, when the distributed network node (112) receives (912) the message (912a) which includes a radio resource control reconfiguration message (912a) and the flag (912b) from the centralized network node (114), and the message (912a) indicates that the message (912a) is directed to the user equipment (110) to perform the inter-centralized unit (114 / 118) handover.

[0231] As shown in block 1804 of FIG. 18, the apparatus embodied by the network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for reading the flag (504b / 912b).

[0232] As shown in block 1806 of FIG. 18, the apparatus embodied by the network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the inter-centralized unit (114 / 118) handover or not. In one or more embodiments, the distributed network node (112) does not (1004) transmit the message (504a) to the centralizednetwork node (114) when an intra-centralized unit (112 / 116) handover (602) is ongoing. In one or more embodiments, the distributed network node (112) determines to transmit (704) the message (504A) to the centralized network node (114) when an intra-centralized unit (112 / 116) handover (602) is not ongoing. In one or more embodiments, the distributed network node (112) is further caused to transmit (914) the message (912a) to the user equipment (110) to perform the intercentralized unit (114 / 118) handover. In one or more embodiments, the distributed network node (112) determines (916), based at least on the message (912a), to withhold an intra-centralized unit (112 / 116) handover command during the inter-centralized unit (114 / 118) handover (904).

[0233] Turning now to FIG. 19, an example flowchart is illustrated for a process 1900 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to transmit a message to a centralized network node (114).

[0234] As shown in block 1902 of FIG. 19, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for enhancing (702) the message (504a) with a second flag (706) to indicate that the intra-centralized unit (112 / 116) handover (602) is ongoing.

[0235] As shown in block 1904 of FIG. 19, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for transmitting (704) the message (504A) to the centralized network node (114).

[0236] Turning now to FIG. 20, an example flowchart is illustrated for a process 2000 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to disregard a message during an inter-centralized unit (114 / 118) handover.

[0237] As shown in block 2002 of FIG. 20, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (802) a second message (802a) to indicate an intra-centralized unit (112 / 116) handover.

[0238] As shown in block 2004 of FIG. 20, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining (1002) that an inter-centralized unit (114 / 118) handover (904) is ongoing.

[0239] As shown in block 2006 of FIG. 20, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for disregarding (804) the second message (802a) to indicate the intra-centralized unit (112 / 116) handover.

[0240] Turning now to FIG. 21, an example flowchart is illustrated for a process 2100 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to determine whether a user equipment (110) is at a border of a serving area (113) associated with the distributed network node (112).

[0241] As shown in block 2102 of FIG. 21, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (1102), from the centralized network node (114) and during a user equipment context request-response (1104), a list of cell identifiers (1106) (cells la...2b) that are in a border of a serving area (113) associated with the distributed network node (112).

[0242] As shown in block 2104 of FIG. 21, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (1108), from the user equipment (110), a measurement report message (1108A) for conditional handover preparation indicating an intra-centralized unit (112 / 116) conditional handover preparation or an inter-centralized unit (114 / 118) conditional handover preparation (1108a).

[0243] As shown in block 2106 of FIG. 21, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining (1112), based on the measurement report message (1108a), whether the user equipment (110) is at the border of the serving area (113) associated with the distributed network node (112). In one or more embodiments, when the distributed network node (112) determines (1112) that the user equipment (110) is at the border of the serving area (113) associated with the distributed network node (112), the distributed network node (112) is further caused by means such as the processing circuitry 220, the communications interface 260, or the like, to transmit (1114), to the centralized network node (114), the measurement report message for the conditional handover preparation (1108a). In one or more embodiments, when the distributed network node (112) determines (1112) that the user equipment (110) is at the border of the servingarea (113) associated with the distributed network node (112), the distributed network node (112) is further caused to transmit (1302) to the user equipment (110), an instruction (1302a) to report only to the centralized network node (114). In one or more embodiments, when the distributed network node (112) determines that the user equipment (110) is not at the border of the serving area (113) associated with the distributed network node (112), the distributed network node (112) is further caused to transmit (1302) to the user equipment (110), an instruction (I l la) to report only to the distributed network node (112).

[0244] Turning now to FIG. 22, an example flowchart is illustrated for a process 2200 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to disregard a measurement report message at an appropriate time.

[0245] As shown in block 2202 of FIG. 22, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (802) a second measurement report message (802a) for the conditional handover preparation indicating the intra-centralized unit (112 / 116) conditional handover preparation.

[0246] As shown in block 2204 of FIG. 22, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for disregarding (1116) the second measurement report message (802a).

[0247] Turning now to FIG. 23, an example flowchart is illustrated for a process 2300 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to determine whether a user equipment (110) is at a border of a serving area associated with the distributed network node (112)

[0248] As shown in block 2302 of FIG. 23, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (1102), from a centralized network node (114) and during a user equipment context request-response (1104), a list of cell identifiers (1106) that are in a border of a serving area (113) associated with the distributed network node (112).

[0249] As shown in block 2304 of FIG. 23, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260,or the like, for receiving (1108), from a user equipment (110), a measurement report message (1108a).

[0250] As shown in block 2306 of FIG. 23, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining (1112), based on the measurement report message (1108a), whether the user equipment (110) is at the border of the serving area (113) associated with the distributed network node (112). In one or more embodiments, when the distributed network node (112) determines (1112) that the user equipment (110) is at the border of the serving area (113) associated with the distributed network node (112), the distributed network node (112) is further caused to transmit (1302) to the user equipment (110), an instruction (1302a) to report only to the centralized network node (114). In one or more embodiments, when the distributed network node (112) determines (1112) that the user equipment (110) is not at the border of the serving area (113) associated with the distributed network node (112), the distributed network node (112) is further caused to transmit (1302) to the user equipment (110), an instruction (1302a) to report only to the distributed unit (112).

[0251] Turning now to FIG. 24, an example flowchart is illustrated for a process 2400 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to initiate intra-centralized network node handover preparation.

[0252] As shown in block 2402 of FIG. 24, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (802), from the user equipment (110), a second measurement report message (802a).

[0253] As shown in block 2404 of FIG. 24, the apparatus embodied by the distributed network node (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for, based on the second measurement report message (802a), initiating (1006) an intracentralized unit (112 / 116) conditional handover preparation.

[0254] Turning now to FIG. 25, an example flowchart is illustrated for a process 2500 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a user equipment (110) in order to transmit a measurement report message to a distributed network node.

[0255] As shown in block 2502 of FIG. 25, the apparatus embodied by the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for adding, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114).

[0256] As shown in block 2504 of FIG. 25, the apparatus embodied by the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for transmitting (504), to a distributed network node (112), the measurement report message (504a).

[0257] In one or more embodiments, the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for intercentralized unit (114 / 118) conditional handover preparation. In one or more embodiments, the user equipment (110) withholds (1202) measurement reporting from the distributed network node (112) based at least on the radio resource control reconfiguration message (912a).

[0258] Turning now to FIG. 26, an example flowchart is illustrated for a process 2600 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a user equipment (110) in order to transmit a measurement report message based on a received instruction.

[0259] As shown in block 2602 of FIG. 26, the apparatus embodied by the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (1302), from a distributed network node (112), an instruction (1302a) to report measurements only to a centralized network node (114) or the distributed network node (112).

[0260] As shown in block 2604 of FIG. 26, the apparatus embodied by the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for transmitting (1304), to the centralized network node (114) or the distributed network node (112), a measurement report message (1304a) based on the received instruction (1302a).

[0261] Turning now to FIG. 27, an example flowchart is illustrated for a process 2700 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinaftergenerally referenced as being embodied by a centralized network node (114) in order to transmit a radio resource control reconfiguration message.

[0262] As shown in block 2702 of FIG. 27, the apparatus embodied by the centralized network node (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for adding, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover or for intercentralized unit (114 / 118) conditional handover preparation.

[0263] As shown in block 2704 of FIG. 27, the apparatus embodied by the centralized network node (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for transmitting (912), to a distributed network node (112), the radio resource control reconfiguration message (912a). In some examples, the user equipment (110) further includes means, such as the processing circuitry 220, the communication interface 260, or the like, for transmitting (1102), to the distributed network node (112) and during a user equipment context request response (1104), a list of cell identifiers (1106) that are in a border of a serving area (113) associated with the distributed network node (112).

[0264] Turning now to FIG. 28, an example flowchart is illustrated for a process 2800 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a centralized network node (114) in order to determine whether to initiate inter-centralized unit (114 / 118) handover.

[0265] As shown in block 2802 of FIG. 28, the apparatus embodied by the centralized network (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing

[0266] As shown in block 2804 of FIG. 28, the apparatus embodied by the centralized network node (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover. In one or more embodiments, when the centralized network node (114) determines (708) that the inter-centralized unit (114 / 118) handover would be better than the intra-centralized unit (112 / 116) handover, the centralized network node (114) isfurther caused to initiate (1008) the inter-centralized unit (114 / 118) handover. In one or more embodiments, when the centralized network node (114) determines (708) that the inter-centralized unit (114 / 118) handover would be better than the intra-centralized unit (112 / 116) handover, the centralized network node (114) is further caused to initiate (1008) the inter-centralized unit (114 / 118) handover. In one or more embodiments, when the centralized network node (114) determines (708) that an inter-centralized unit (114 / 118) handover would not be better than the intra-centralized unit (112 / 116) handover, the centralized network node (114) disregards (1012) the measurement report message (504a).

[0267] Turning now to FIG. 29, an example flowchart is illustrated for a process 2900 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a centralized network node (114) in order to initiate an intra-centralized unit (112 / 116) handover or an inter-centralized unit (114 / 118) handover.

[0268] As shown in block 2902 of FIG. 29, the apparatus embodied by the centralized network (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for transmitting (1102), to the distributed network node (112) and during a user equipment context request response (1104), a list of cell identifiers (1106) that are in a border of a serving area (113) associated with the distributed network node (112).

[0269] As shown in block 2904 of FIG. 29, the apparatus embodied by the centralized network (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (1304), from a user equipment (110), a measurement report message (1304a).

[0270] As shown in block 2906 of FIG. 29, the apparatus embodied by the centralized network (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for, based on the measurement report message (1304a), initiate (1306) an intra-centralized unit (112 / 116) handover or an inter-centralized unit (114 / 118) handover.

[0271] Turning now to FIG. 30, an example flowchart is illustrated for a process 3000 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a distributed network node (112) in order to transmit or disregard a measurement report message.

[0272] As shown in block 3002 of FIG. 30, the apparatus embodied by the distributed network (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (1502), from a user equipment (110), a measurement report message (1502a)after an intra-centralized unit (112 / 116) conditional handover configuration is sent to a user equipment, wherein the measurement report message (1502a) is intended for a centralized network node (114).

[0273] As shown in block 3004 of FIG. 30, the apparatus embodied by the distributed network (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining (1504), based on the measurement report message (1502a), whether intercentralized unit (114 / 118) cells have a better signal level than intra-centralized unit (112 / 116) cells.

[0274] As shown in block 3006 of FIG. 30, the apparatus embodied by the distributed network (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for, when the inter-centralized unit (114 / 118) cells have the better signal level than the intra-centralized unit (112 / 116) cells, transmitting (1506) the measurement report message (1502a) to the centralized unit.

[0275] As shown in block 3008 of FIG. 30, the apparatus embodied by the distributed network (112) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for, when the inter-centralized unit (114 / 118) cells do not have the better signal level than the intra-centralized unit (112 / 116) cells, disregarding (1702) the measurement report message (1502a).

[0276] Turning now to FIG. 31, an example flowchart is illustrated for a process 3100 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a user equipment (110) in order to modify execution conditions.

[0277] As shown in block 3102 of FIG. 31, the apparatus embodied by the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for receiving (1602), from a centralized network node (114), a configuration (1602a) describing conditions for intra-centralized unit (112 / 116) conditional handover modification.

[0278] As shown in block 3104 of FIG. 31, the apparatus embodied by the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining, based on the configuration (1602a), that the conditions for intra-centralized unit (112 / 116) conditional handover modification are satisfied.

[0279] As shown in block 3106 of FIG. 31, the apparatus embodied by the user equipment (110) includes means, such as the processing circuitry 220, the communication interface 260, or the like,for modifying (1606) execution conditions (1608) for intra-centralized unit (112 / 116) conditional handover based at least on the configuration (1602a).

[0280] Turning now to FIG. 32, an example flowchart is illustrated for a process 3200 performed by an apparatus embodied by, associated with or otherwise in communication with (hereinafter generally referenced as being embodied by a centralized network node (114) in order to modify execution conditions.

[0281] As shown in block 3202 of FIG. 32, the apparatus embodied by the centralized network node (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for determining a configuration (1602a) describing conditions (1608) for intracentralized unit (112 / 116) conditional handover modification.

[0282] As shown in block 3204 of FIG. 32, the apparatus embodied by the centralized network node (114) includes means, such as the processing circuitry 220, the communication interface 260, or the like, for transmitting (1602), to a user equipment (110), the configuration (1602a).

[0283] FIGS. 18-32 illustrate flowcharts depicting methods according to an example embodiment of the present disclosure. It will be understood that each block of the flowcharts and combination of blocks in the flowcharts may be implemented by various means, such as hardware, firmware, processor, circuitry, and / or other communication devices associated with execution of software including one or more computer program instructions. For example, one or more of the procedures described above may be embodied by computer program instructions. In this regard, the computer program instructions which embody the procedures described above may be stored by a memory device 240 of an apparatus employing an embodiment and executed by a processor 220. As will be appreciated, any such computer program instructions may be loaded into a computer or other programmable apparatus (for example, hardware) to produce a machine, such that the resulting computer or other programmable apparatus implements the functions specified in the flowchart blocks. These computer program instructions may also be stored in a computer-readable memory that may direct a computer or other programmable apparatus to function in a particular manner, such that the instructions stored in the computer- readable memory produce an article of manufacture the execution of which implements the function specified in the flowchart blocks. The computer program instructions may also be loaded into a computer or other programmable apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide operations for implementing the functions specified in the flowchart blocks.

[0284] Accordingly, blocks of the flowcharts support combinations of means for performing the specified functions and combinations of operations for performing the specified functions for performing the specified functions. It will also be understood that one or more blocks of the flowcharts, and combinations of blocks in the flowcharts, may be implemented by special purpose hardware-based computer systems which perform the specified functions, or combinations of special purpose hardware and computer instructions.

[0285] In one or more embodiments, a distributed network node (112) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the distributed network node (112) to receive (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for inter-centralized unit (114 / 118) handover. The distributed network node (112) is further caused to read the flag (504b / 912b). The distributed network node (112) is further caused to determine (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the intercentralized unit (114 / 118) handover or not.

[0286] In one or more embodiments, when the distributed network node (112) receives (504) the message from the user equipment (110), the message comprises a measurement report message (504a), and the flag (504b) further indicates that the message is directed to the centralized network node (114).

[0287] In one or more embodiments, the distributed network node (112) does not (1004) transmit the message (504a) to the centralized network node (114) when an intra-centralized unit (112 / 116) handover (602) is ongoing.

[0288] In one or more embodiments, when an intra-centralized unit (112 / 116) handover (602) is ongoing, the distributed network node (112) is further caused to enhance (702) the message (504a) with a second flag (706) to indicate that the intra-centralized unit (112 / 116) handover (602) is ongoing. The distributed network node (112) is further caused to transmit (704) the message (504A) to the centralized network node (114).

[0289] In one or more embodiments, the distributed network node (112) determines to transmit (704) the message (504A) to the centralized network node (114) when an intra-centralized unit (112 / 116) handover (602) is not ongoing.

[0290] In one or more embodiments, the distributed network node (112) is further caused to receive (802) a second message (802a) to indicate the intra-centralized unit (112 / 116) handover. The distributed network node (112) is further caused to determine (1002) that the intercentralized unit (114 / 118) handover (904) is ongoing. The distributed network node (112) is further caused to disregard (804) the second message (802a) to indicate the intra-centralized unit (112 / 116) handover.

[0291] In one or more embodiments, the distributed network node (112) receives (912) the message (912a) which comprises a radio resource control reconfiguration message (912a) and the flag (912b) from the centralized network node (114), and the message (912a) indicates that the message (912a) is directed to the user equipment (110) to perform the inter-centralized unit (114 / 118) handover.

[0292] In one or more embodiments, the distributed network node (112) is further caused to transmit (914) the message (912a) to the user equipment (110) to perform the inter-centralized unit (114 / 118) handover.

[0293] In one or more embodiments, the distributed network node (112) determines (916), based at least on the message (912a), to withhold an intra-centralized unit (112 / 116) handover command during the inter-centralized unit (114 / 118) handover (904).

[0294] In one or more embodiments, a user equipment (110) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the user equipment (110) to add, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The user equipment (110) is further caused to transmit (504), to a distributed network node (112), the measurement report message (504a).

[0295] In one or more embodiments, a user equipment (110) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the user equipment (110) to receive (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resourcecontrol reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover .

[0296] In one or more embodiments, a centralized network node (114) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the centralized network node (114) to add, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The centralized network node (114) is further caused to transmit (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0297] In one or more embodiments, a centralized network node (114) is provided, including at least one processor and at least one memory storing instructions that, when executed by the processor, cause the centralized network node (114) to receive (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The centralized network node (114) is further caused to determine (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.

[0298] In one or more embodiments, when the centralized network node (114) determines (708) that the inter-centralized unit (114 / 118) handover would be better than the intra-centralized unit (112 / 116) handover, the centralized network node (114) is further caused to initiate (1008) the inter-centralized unit (114 / 118) handover.

[0299] In one or more embodiments, when the centralized network node (114) determines (708) that the inter-centralized unit (114 / 118) handover would not be better than the intra-centralized unit (112 / 116) handover, the centralized network node (114) disregards (1012) the measurement report message (504a).

[0300] In one or more embodiments, a computer-implemented method is provided that is performed by a distributed network node (112) and includes receiving (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for intercentralized unit (114 / 118) handover. The method further includes reading the flag (504b / 912b). The method further includes determining (506), based at least on the flag (504b / 912b), whetherto transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the inter-centralized unit (114 / 118) handover or not.

[0301] In one or more embodiments, when the distributed network node (112) receives (504) the message from the user equipment (110), the message comprises a measurement report message (504a), and the flag (504b) further indicates that the message is directed to the centralized network node (114).

[0302] In one or more embodiments, the distributed network node (112) does not (1004) transmit the message (504a) to the centralized network node (114) when an intra-centralized unit (112 / 116) handover (602) is ongoing.

[0303] In one or more embodiments, when an intra-centralized unit (112 / 116) handover (602) is ongoing, the method further includes enhancing (702) the message (504a) with a second flag (706) to indicate that the intra-centralized unit (112 / 116) handover (602) is ongoing. The method further includes transmitting (704) the message (504A) to the centralized network node (114).

[0304] In one or more embodiments, the distributed network node (112) determines to transmit (704) the message (504A) to the centralized network node (114) when an intra-centralized unit (112 / 116) handover (602) is not ongoing.

[0305] In one or more embodiments, the method further includes receiving (802) a second message (802a) to indicate the intra-centralized unit (112 / 116) handover. The method further includes determining (1002) that the inter-centralized unit (114 / 118) handover (904) is ongoing. The method further includes disregarding (804) the second message (802a) to indicate the intra- centralized unit (112 / 116) handover.

[0306] In one or more embodiments, the distributed network node (112) receives (912) the message (912a) which comprises a radio resource control reconfiguration message (912a) and the flag (912b) from the centralized network node (114), and the message (912a) indicates that the message (912a) is directed to the user equipment (110) to perform the inter-centralized unit (114 / 118) handover.

[0307] In one or more embodiments, the method further includes transmitting (914) the message (912a) to the user equipment (110) to perform the inter-centralized unit (114 / 118) handover.

[0308] In one or more embodiments, the distributed network node (112) determines (916), based at least on the message (912a), to withhold an intra-centralized unit (112 / 116) handover command during the inter-centralized unit (114 / 118) handover (904).

[0309] In one or more embodiments, a computer-implemented method is provided that is performed by a user equipment (110) and includes adding, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The method further includes transmitting (504), to a distributed network node (112), the measurement report message (504a).

[0310] In one or more embodiments, a computer-implemented method is provided that is performed by a user equipment (110) and includes receiving (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover.

[0311] In one or more embodiments, a computer-implemented method is provided that is performed by a centralized network node (114) and includes adding, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The method includes transmitting (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0312] In one or more embodiments, a computer-implemented method is provided that is performed by a centralized network node (114) and includes receiving (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The method further includes determining (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.

[0313] In one or more embodiments, when the centralized network node (114) determines (708) that the inter-centralized unit (114 / 118) handover would be better than the intra-centralized unit (112 / 116) handover, the method further includes initiating (1008) the inter-centralized unit (114 / 118) handover.

[0314] In one or more embodiments, when the centralized network node (114) determines (708) that the inter-centralized unit (114 / 118) handover would not be better than the intra-centralizedunit (112 / 116) handover, the centralized network node (114) disregards (1012) the measurement report message (504a).

[0315] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a distributed network node (112), cause the distributed network node (112) to receive (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for inter-centralized unit (114 / 118) handover. The distributed network node (112) is further caused to read the flag (504b / 912b). The distributed network node (112) is further caused to determine (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the intercentralized unit (114 / 118) handover or not.

[0316] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to add, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The user equipment (110) is further caused to transmit (504), to a distributed network node (112), the measurement report message (504a).

[0317] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to receive (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover.

[0318] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to add, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The centralized network node (114) is further caused to transmit (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0319] In one or more embodiments, a non-transitory computer readable storage medium is provided including computer instructions that, when executed by a user equipment (110), cause the user equipment (110) to receive (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The centralized network node (114) is further caused to determine (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.

[0320] In one or more embodiments, a distributed network node (112) is provided that includes means for receiving (504 / 912), from a user equipment (110) or a centralized network node (114), a message (504a / 912a), wherein a message header of the message comprises a flag (504b / 912b) indicating that the message is for inter-centralized unit (114 / 118) handover. The distributed network node (112) further includes means for reading the flag (504b / 912b). The distributed network node further includes means for determining (506), based at least on the flag (504b / 912b), whether to transmit (704 / 914) or not to transmit the message to one of the user equipment (110) or the centralized network node (114) to perform the inter-centralized unit (114 / 118) handover or not.

[0321] In one or more embodiments, a user equipment (110) is provided that includes means for adding, to a message header of a measurement report message (504a), a flag (504b), wherein the flag (504b) indicates that the measurement report message (504a) is directed to a centralized network node (114). The user equipment (110) further includes means for transmitting (504), to a distributed network node (112), the measurement report message (504a).

[0322] In one or more embodiments, a user equipment (110) is provided that includes means for receiving (914), from a distributed network node (112), a radio resource control reconfiguration message (912a), wherein a message header of the radio resource control reconfiguration message (912a) comprises a flag (912b) indicating that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover.

[0323] In one or more embodiments, a centralized network node (114) is provided that includes means for adding, to a message header of a radio resource control reconfiguration message (912a), a flag (912b), wherein the flag (912b) indicates that the radio resource control reconfiguration message (912a) is for inter-centralized unit (114 / 118) handover. The centralizednetwork node (114) includes means for transmitting (912), to a distributed network node (112), the radio resource control reconfiguration message (912a).

[0324] In one or more embodiments, a centralized network node (114) is provided that includes means for receiving (704), from a distributed network node (112), a measurement report message (504a), wherein a message header of the measurement report message comprises a flag (706) indicating that an intra-centralized unit (112 / 116) handover (602) is ongoing. The centralized network node (114) includes means for determining (708), based at least on the flag (706), whether to initiate (1008) an inter-centralized unit (114 / 118) handover.

[0325] Many modifications and other embodiments set forth herein will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.

[0326] Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and / or functions, it should be appreciated that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and / or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

What is claimed is:

1. A distributed network node, comprising: at least one processor; and at least one memory storing instructions that, when executed by the processor, cause the distributed network node to perform: receive, from a user equipment or a centralized network node, a message, wherein a message header of the message comprises a flag indicating that the message is for intercentralized unit handover; read the flag; and determine, based at least on the flag, whether to transmit or not to transmit the message to one of the user equipment or the centralized network node to perform the inter-centralized unit handover or not.

2. The distributed network node of claim 1 , wherein when the distributed network node receives the message from the user equipment, the message comprises a measurement report message, and the flag further indicates that the message is directed to the centralized network node.

3. The distributed network node of claim 2, wherein the distributed network node does not transmit the message to the centralized network node when an intra-centralized unit handover is ongoing.

4. The distributed network node of claim 2, wherein when an intra-centralized unit handover is ongoing, the distributed network node is further caused to: enhance the message with a second flag to indicate that the intra-centralized unit handover is ongoing; and transmit the message to the centralized network node.

5. The distributed network node of claim 2, wherein the distributed network node determines to transmit the message to the centralized network node when an intra-centralized unit handover is not ongoing.

6. The distributed network node of claim 5, wherein the distributed network node is further caused to: receive a second message to indicate the intra-centralized unit handover; determine that the inter-centralized unit handover is ongoing; and disregard the second message to indicate the intra-centralized unit handover.

7. The distributed network node of claim 1 , wherein the distributed network node receives the message which comprises a radio resource control reconfiguration message and the flag from the centralized network node, and the message indicates that the message is directed to the user equipment to perform the inter-centralized unit handover.

8. The distributed network node of claim 7, wherein the distributed network node is further caused to transmit the message to the user equipment to perform the inter-centralized unit handover.

9. The distributed network node of claim 7, wherein the distributed network node determines, based at least on the message, to withhold an intra-centralized unit handover command during the inter-centralized unit handover.

10. A user equipment, comprising: at least one processor; and at least one memory storing instructions that, when executed by the processor, cause the user equipment to perform: add, to a message header of a measurement report message, a flag, wherein the flag indicates that the measurement report message is directed to a centralized network node; and transmit, to a distributed network node, the measurement report message.

11. A user equipment, comprising: at least one processor; andat least one memory storing instructions that, when executed by the processor, cause the user equipment to perform: receive, from a distributed network node, a radio resource control reconfiguration message, wherein a message header of the radio resource control reconfiguration message comprises a flag indicating that the radio resource control reconfiguration message is for intercentralized unit handover.

12. A centralized network node, comprising: at least one processor; and at least one memory storing instructions that, when executed by the processor, cause the centralized network node to perform: add, to a message header of a radio resource control reconfiguration message, a flag, wherein the flag indicates that the radio resource control reconfiguration message is for intercentralized unit handover; and transmit, to a distributed network node, the radio resource control reconfiguration message.

13. A centralized network node, comprising: at least one processor; and at least one memory storing instructions that, when executed by the processor, cause the centralized network node to perform: receive, from a distributed network node, a measurement report message, wherein a message header of the measurement report message comprises a flag indicating that an intracentralized unit handover is ongoing; and determine, based at least on the flag, whether to initiate an inter-centralized unit handover.

14. The centralized network node of claim 13, wherein when the centralized network node determines that the inter-centralized unit handover would be better than the intracentralized unit handover, the centralized network node is further caused to initiate the intercentralized unit handover.

15. The centralized network node of claim 13, wherein when the centralized network node determines that the inter-centralized unit handover would not be better than the intracentralized unit handover, the centralized network node disregards the measurement report message.

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