Configuration and UE method for implementing inter-cu l1 / l2 triggered mobility (ltm)

Abstract

An apparatus of a next generation NodeB (gNB), the apparatus comprising one or more processors coupled to memory and configured to determine, at a source central unit (CU) of the gNB, candidate CUs for a user equipment (UE). The processor transmits a handover request from the source CU to a candidate CU. The processor receives, at the source CU from the candidate CU, a handover request acknowledgement containing information about candidate distributed units (DUs) coupled to the candidate CU to form a list of candidate DUs. The processor allocates, at the source CU, indices for the candidate DUs coupled to the candidate CU. The processor encodes, at the source CU, a radio resource control (RRC) message containing the list of candidate DUs coupled to one or more candidate CUs and the allocated indices for transmission to the UE via a source DU.

Description

Technical Field

[0001] Embodiments of the present invention relate to wireless communication, including apparatus, systems, and methods for implementing layer 1 / layer 2 triggered mobility (LTM) between centralized units (CUs).

[0002] Related technical descriptions The use of wireless communication systems is growing rapidly. In recent years, wireless devices, such as smartphones and tablets, have become increasingly complex and sophisticated. In addition to supporting telephone calls, many mobile devices now offer access to the Internet, email, text messaging, and navigation using the Global Positioning System (GPS), and are capable of operating complex applications that utilize these functionalities.

[0003] Long Term Evolution (LTE) has become the technology of choice for most wireless network operators worldwide, providing mobile broadband data and high-speed internet access to their user base. LTE was first proposed in 2004 and standardized for the first time in 2008. Since then, with the exponential growth in the use of wireless communication systems, the demand from wireless network operators to support higher capacity for a higher density of mobile broadband users has also increased. Research into new radio access technologies began in 2015, and in 2017, the first version of 5G New Radio (5G NR) was standardized.

[0004] 5G-NR (also known as NR for short) offers higher capacity for higher density mobile broadband users compared to LTE, while also supporting ultra-reliable and massive machine-type communication between devices, as well as lower latency and / or lower battery consumption. Additionally, NR allows for more flexible UE scheduling compared to current LTE. Therefore, ongoing development of 5G-NR is underway to take advantage of the potentially higher throughput at higher frequencies. Summary of the Invention

[0005] The implementation relates to wireless communication, and more specifically to apparatus, systems, and methods for a next-generation Node B (gNB) device, the apparatus including one or more processors coupled to a memory. The processor is configured to: determine one or more candidate CUs for a User Equipment (UE) at a source centralized unit (CU) of the gNB. The processor is configured to: transmit a handover request from the source CU of the gNB to the one or more candidate CUs. The processor is configured to: receive a handover request acknowledgment at the source CU of the gNB from the one or more candidate CUs, the handover request acknowledgment containing information about candidate distributed units (DUs) coupled to each of the one or more candidate CUs, to form a list of candidate DUs. The processor is configured to: assign an index to the candidate DUs coupled to the one or more candidate CUs at the source CU of the gNB. The processor is configured to: encode a Radio Resource Control (RRC) message at the source CU of the gNB, the RRC message containing the list of candidate DUs coupled to the one or more candidate CUs and the assigned index, for transmission to the UE via the source DUs of the gNB.

[0006] Other implementations relate to a method for Layer 1 / Layer 2 triggered mobility (LTM) between central units (CUs) at a next-generation node B (gNB). The method includes: identifying one or more candidate CUs for a user equipment (UE) at a source CU of the gNB. The method includes: transmitting a handover request from the source CU of the gNB to the one or more candidate CUs. The method includes: receiving a handover request acknowledgment at the source CU of the gNB from the one or more candidate CUs, the handover request acknowledgment containing information about candidate distributed units (DUs) coupled to the one or more candidate CUs, to form a list of candidate DUs. The method includes: assigning an index to the candidate DUs coupled to the one or more candidate CUs at the source CU of the gNB. The method includes: encoding a radio resource control (RRC) message at the source CU of the gNB, the RRC message containing the list of candidate DUs coupled to the one or more candidate CUs and the assigned index, for transmission to the UE via the source DUs of the gNB.

[0007] The technologies described herein can be implemented in and / or used with a variety of different types of devices, including but not limited to unmanned aerial vehicles (UAVs), unmanned controllers (UACs), base stations, access points, cellular phones, tablet computers, wearable computing devices, portable media players, and any of a variety of other computing devices.

[0008] The present invention is intended to provide a brief overview of some of the subjects described in this document. Therefore, it should be understood that the features described above are merely illustrative and should not be construed as narrowing the scope or substance of the subjects described herein in any way. Other features, aspects, and advantages of the subjects described herein will become apparent from the following detailed description, drawings, and claims. Attached Figure Description

[0009] A better understanding of the subject matter can be obtained by considering the following detailed description of various embodiments in conjunction with the accompanying drawings, in which: Figure 1A Example wireless communication systems according to some implementation schemes are illustrated.

[0010] Figure 1B Examples of base stations and access points communicating with user equipment (UE) devices according to some implementation schemes are illustrated.

[0011] Figure 2 Example block diagrams of base stations according to some implementation schemes are shown.

[0012] Figure 3 Example block diagrams of servers according to some implementation schemes are shown.

[0013] Figure 4 Example block diagrams of a UE according to some implementation schemes are shown.

[0014] Figure 5 Example block diagrams of cellular communication circuits according to some implementation schemes are shown.

[0015] Figure 6 Examples of baseband processor architectures for UEs according to some implementation schemes are illustrated.

[0016] Figure 7 Example block diagrams illustrating the interface of a baseband circuit according to some implementation schemes are shown.

[0017] Figure 8 Examples of control plane protocol stacks based on some implementation schemes are shown.

[0018] Figure 9 Examples of user plane protocol stacks based on some implementation schemes are shown.

[0019] Figure 10 Example components of the core network according to some implementation schemes are shown.

[0020] Figure 11 Example diagrams of intra-CU and inter-CU LTM cell handover are provided according to some implementation schemes.

[0021] Figure 12Example diagrams of intra-CU and inter-CU LTM cell handover are provided according to some implementation schemes.

[0022] Figure 13 Examples of signaling for LTM handover between CUs are illustrated according to some implementation schemes.

[0023] Figure 14 A flowchart illustrating an example of a method for triggering mobility (LTM) between central units (CUs) layer 1 / layer 2 according to some implementation schemes is provided.

[0024] Figure 15 Examples of signaling for LTM handover between CUs are illustrated according to some implementation schemes.

[0025] Figure 16 Examples of MAC CEs for transmitting information according to some implementation schemes are shown.

[0026] Figure 17 Examples of MAC CEs for transmitting information according to some implementation schemes are shown.

[0027] Figure 18 Examples of signaling for LTM handover between CUs are illustrated according to some implementation schemes.

[0028] Figure 19 Examples of MAC CEs for transmitting information according to some implementation schemes are shown.

[0029] Figure 20 Examples of ASN.1 code for configuring SIB1 for the network are shown according to some implementation schemes.

[0030] Figure 21 Examples of MAC CEs for transmitting information according to some implementation schemes are shown.

[0031] Figure 22 Examples of LTM switching based on some implementation schemes are illustrated.

[0032] Although the features described herein may be subject to various modifications and alternatives, specific embodiments thereof are shown by way of example in the accompanying drawings and described in detail herein. However, it should be understood that the drawings and their detailed description are not intended to limit one to the specific forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the substance and scope of the subject matter as defined by the appended claims. Detailed Implementation

[0033] the term The following is a glossary of terms used in this disclosure: Memory media—any of various types of nontransitory memory devices or storage devices. The term "memory media" is intended to include mounting media, such as CD-ROMs, floppy disks, or magnetic tape devices; computer system memory or random access memory, such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory, such as flash memory; magnetic media, such as hard disk drives or optical storage devices; registers or other similar types of memory elements, etc. Memory media may also include other types of nontransitory memory or combinations thereof. Furthermore, memory media may reside in a first computer system executing a program, or may reside in a different second computer system connected to the first computer system via a network such as the Internet. In the latter example, the second computer system may provide program instructions to the first computer for execution. The term "memory media" may include two or more memory media residing in different locations in different computer systems connected via, for example, a network. Memory media may store program instructions (e.g., embodied in a computer program) that can be executed by one or more processors.

[0034] Carrier media—such as memory media as described above, and physical transmission media such as buses, networks, and / or other physical transmission media that transmit signals such as electrical signals, electromagnetic signals, or digital signals.

[0035] Programmable hardware elements encompass a variety of hardware devices, which consist of multiple programmable functional blocks connected via programmable interconnects. Examples include FPGAs (Field-Programmable Gate Arrays), PLDs (Programmable Logic Devices), FPOAs (Field-Programmable Object Arrays), and CPLDs (Complex PLDs). Programmable functional blocks can range from fine-grained (combinational logic or lookup tables) to coarse-grained (arithmetic logic units or processor cores). Programmable hardware elements may also be referred to as "configurable logic units."

[0036] Computer system (or computer) — any of the various types of computing or processing systems, including personal computer systems (PCs), mainframe computer systems, workstations, network appliances, internet-connected appliances, personal digital assistants (PDAs), television systems, grid computing systems, or other devices or combinations thereof. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0037] User equipment (UE) (or “UE device”) — any of various types of computer system devices that are mobile or portable and perform wireless communication. Examples of UE devices include mobile phones or smartphones (e.g., iPhone). ™Based on Android ™ Telephones), portable gaming devices (e.g., Nintendo DS) ™ PlayStation Portable ™ Gameboy Advance ™ iPhone ™ ), laptops, wearable devices (e.g., smartwatches, smart glasses), PDAs, portable internet devices, music players, data storage devices, other handheld devices, unmanned aerial vehicles (UAVs) (e.g., drones), UAV controllers (UACs), etc. Generally speaking, the term "UE" or "UE device" can be broadly defined to encompass any electronic device, computing device, and / or telecommunications device (or combination of devices) that is easily transportable by the user and capable of wireless communication.

[0038] Base station—The term “base station” has the full range of its common meaning and includes at least a wireless communication station that is installed in a fixed location and is used for communication as part of a wireless telephone system or radio system.

[0039] A processing element (or processor) is a component or combination of components capable of performing the functions of a device such as a user equipment or cellular network device. A processing element may include, for example: a processor and associated memory, portions or circuitry of individual processor cores, an entire processor core, a processor array, circuitry such as an ASIC (Application-Specific Integrated Circuit), programmable hardware components such as a Field-Programmable Gate Array (FPGA), and any combination thereof.

[0040] A channel is a medium used to transmit information from a transmitter to a receiver. It should be noted that because the characteristics of the term "channel" can vary depending on the wireless protocol, the term "channel" as used herein can be considered to be used in a standard manner consistent with the type of device to which the term is referenced. In some standards, channel bandwidth can be variable (e.g., depending on device capabilities, frequency band conditions, etc.). For example, LTE can support scalable channel bandwidths from 1.4 MHz to 20 MHz. 5G NR can support scalable channel bandwidths from 5 MHz to 100 MHz in Frequency Range 1 (FR1) and up to 400 MHz in FR2. In other radio access technologies, WLAN channels can be 22 MHz wide, while Bluetooth channels can be 1 MHz wide. Other protocols and standards may include different definitions of channels. Furthermore, some standards may define and use multiple types of channels, for example, different channels for uplink or downlink and / or different channels for different purposes such as data, control information, etc.

[0041] Frequency band—The term “frequency band” has the full range of its general meaning and includes at least a segment of spectrum (e.g., radio frequency spectrum) in which a channel is used or reserved for the same purpose.

[0042] Automatic—means that an action or operation is performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuits, programmable hardware elements, ASICs, etc.) without requiring direct specification or execution of the action or operation through user input. Therefore, the term "automatically" is the opposite of an operation performed or specified manually by a user, where the user provides input to directly perform the operation. An automatic process can be initiated by user-provided input, but the subsequent actions performed "automatically" are not specified by the user; that is, they are not performed "manually," where the user specifies each action to be performed. For example, a user filling out a form by selecting each field and providing input specifying information (e.g., by typing information, selecting a checkbox, radio selection, etc.) is considered manually filling out the form, even though the computer system will update the form in response to the user's actions. The form can be automatically filled out by a computer system, where the computer system (e.g., software executed on the computer system) analyzes the fields of the form and fills out the form without any user input specifying answers for the fields. As indicated above, the user can invoke the automatic filling of the form but does not participate in the actual filling of the form (e.g., the user does not manually specify answers for the fields, but they are completed automatically). This manual provides various examples of operations that are automatically performed in response to actions taken by the user.

[0043] Approximately—means a value close to the correct or precise value. For example, approximately could mean a value within 1% to 10% of the precise (or expected) value. However, it should be noted that the actual threshold (or tolerance) can be application-dependent. For example, in some implementations, “approximately” may mean within 0.1% of a specified or expected value, while in various other implementations, the threshold may be, for example, 2%, 3%, 5%, etc., depending on the expectations or settings of the specific application.

[0044] Concurrency refers to the parallel execution or implementation of tasks, processes, or programs in a manner that at least partially overlaps. For example, concurrency can be achieved using “strong” or strict parallelism, where tasks are executed in parallel (at least partially) on corresponding computing elements; or using “weak parallelism,” where tasks are executed in an interleaved manner (e.g., by time multiplexing of execution threads).

[0045] The legacy system—the 3rd Generation Partnership Project (3GPP)—develops specifications that define 3GPP technologies. 3GPP specifications cover cellular telecommunications technologies, including radio access, core network, and service capabilities, providing a complete system description for mobile telecommunications. 3GPP uses a system of parallel “releases,” which provide developers with a stable platform for implementing features at a given point and then allow for the addition of new functionality in subsequent releases. Release 17 was released in 2022. At the time of this disclosure, Release 18 (Rel-18) is due for release on June 22, 2024, as its specifications are largely finalized. Therefore, specific implementations and concepts compatible with Rel-18 or earlier releases are sometimes referred to herein as “legacy releases.” One or more implementations of this disclosure may be adopted in future releases (e.g., Release 19).

[0046] Centralized and Distributed Units—Base stations such as gNBs can be divided into physical entities called Centralized Units (CUs) and Distributed Units (DUs). CUs provide support for higher layers of the protocol stack, such as the Radio Resource Control (RRC) layer and the Packet Data Convergence Protocol (PDCP) layer. DUs provide support for lower layers of the protocol stack, such as the Media Access Control (MAC) layer and the physical layer. A gNB may have a single CU coupled to and controlling multiple DUs. Each DU may support one or more cells.

[0047] Various components can be described as being "configured" to perform one or more tasks. In this context, "configured" is a broad expression generally meaning "having a structure" that performs one or more tasks during operation. Therefore, a component can be configured to perform a task even when it is not currently performing one (e.g., a set of electrical conductors can be configured to electrically connect one module to another, even when the two modules are not connected). In some contexts, "configured" can be a broad expression generally meaning "having a circuit" that performs one or more tasks during operation. Therefore, a component can be configured to perform a task even when it is not currently switched on. Typically, the circuit forming the structure corresponding to "configured" can include hardware circuitry.

[0048] For ease of description, various components may be described as performing one or more tasks. Such descriptions should be interpreted as including the phrase "configured to". Statements describing a component as configured to perform one or more tasks are explicitly intended not to invoke the interpretation of 35 USC § 112(f) for that component.

[0049] The example embodiments can be further understood by referring to the following description and related figures, wherein the same elements have the same reference numerals. The example embodiments relate to configurations and methods for implementing inter-CU LTM.

[0050] The example implementation is described in relation to communication between the source CU and candidate CU of the next-generation node B (gNB) to obtain information about target or candidate distributed units (DUs) for the candidate CU used by the user equipment (UE). However, references to the gNB or UE are provided for illustrative purposes only. The example implementation can be used with any electronic component that can establish a connection to the network and is configured using hardware, software, and / or firmware to support inter-CU LTM. Therefore, the gNB or UE described herein is used to represent any suitable type of electronic component.

[0051] Throughout this specification, various information elements (IEs) are referred to by specific names. It should be understood that these names are merely examples, and the IEs carrying the information referenced throughout this specification may be referenced by various entities under other names.

[0052] Figure 1A and Figure 1B Communication system Figure 1A A simplified example wireless communication system according to some implementation schemes is illustrated. It should be noted that... Figure 1A The system described herein is merely one example of a possible system, and the features of this disclosure can be implemented in any of a variety of systems as needed.

[0053] As shown in the figure, the example wireless communication system includes a base station 102A, which communicates with one or more user equipments 106A, 106B to 106N, etc., via a transmission medium. Each user equipment may be referred to herein as a "user equipment" (UE). Therefore, user equipment 106 is referred to as a UE or UE device.

[0054] Base station (BS) 102A may be a transceiver base station (BTS) or a cell site (“cellular base station”), and may include hardware that enables wireless communication with UE 106A to UE 106N.

[0055] The communication area (or coverage area) of a base station may be referred to as a "cell". Base station 102A and UE 106 can be configured to communicate via a transmission medium using any of a variety of Radio Access Technologies (RATs), also known as wireless communication technologies or telecommunications standards, such as GSM, UMTS (associated with air interfaces such as WCDMA or TD-SCDMA), LTE, LTE-Advanced (LTE-A), 5G New Radio (5G NR), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc. Note that if base station 102A is implemented in the context of LTE (also known as Evolved Universal Terrestrial Radio Access Network (E-UTRAN), its alternative location may be referred to as 'eNodeB' or 'eNB'. Note that if base station 102A is implemented in a 5G NR environment, its alternative location may be referred to as "gNodeB" or "gNB".

[0056] As shown in the figure, base station 102A can also be configured to communicate with network 100 (e.g., in various possibilities, the core network of a cellular service provider, telecommunications networks such as the Public Switched Telephone Network (PSTN), and / or the Internet). Therefore, base station 102A facilitates communication between user equipments and / or between user equipments and network 100. Specifically, cellular base station 102A can provide UE 106 with various telecommunications capabilities, such as voice, SMS, and / or data services.

[0057] Base station 102A and other similar base stations (such as base stations 102B, ..., 102N) operating according to the same or different cellular communication standards can therefore be provided as a network of cells that can provide continuous or nearly continuous overlapping services to UE 106A-106N and similar devices over a geographical area via one or more cellular communication standards.

[0058] Therefore, although base station 102A can act as such Figure 1A The illustrated UE 106A-N is a "serving cell," but each UE 106 may also be able to receive signals (and possibly within its communication range) from one or more other cells (which may be provided by base stations 102B-N and / or any other base stations), which may be referred to as "neighboring cells." Such cells may also facilitate communication between user equipments and / or between user equipments and network 100. These cells may include "macro" cells, "micro" cells, "pecimen" cells, and / or any other cells of various other granularities providing a service area size. For example, Figure 1A The illustrated base station 102A-B could be a macro cell, while base station 102N could be a micro cell. Other configurations are also possible.

[0059] In some implementations, base station 102A may be a next-generation base station, such as a 5G New Radio (5G NR) base station or a “gNB”. In some implementations, the gNB may be connected to a legacy evolved packet core (EPC) network and / or to an NR core (NRC) network. Furthermore, a gNB cell may include one or more transition and receive points (TRPs). Additionally, a UE capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs.

[0060] It should be noted that UE 106 may be able to communicate using multiple wireless communication standards. For example, UE 106 may be configured to communicate using wireless networking (e.g., Wi-Fi) and / or peer-to-peer wireless communication protocols (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.) other than at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD, etc.)). If desired, UE 106 may also be configured, or alternatively, to communicate using one or more Global Navigation Satellite Systems (GNSS, such as GPS or GLONASS), one or more mobile television broadcasting standards (e.g., ATSC-M / H or DVB-H) and / or any other wireless communication protocol. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0061] Figure 1B User equipment 106 (e.g., one of devices 106A to 106N) communicating with base station 102 and access point 112 according to some embodiments is illustrated. UE 106 can be a device with cellular and non-cellular communication capabilities (e.g., Bluetooth, Wi-Fi, etc.), such as a mobile phone, handheld device, computer or tablet computer, or virtually any type of wireless device.

[0062] UE 106 may include a processor configured to execute program instructions stored in memory. UE 106 may execute any method implementation of the method implementations described herein by executing such stored instructions. Alternatively or additionally, UE 106 may include programmable hardware elements, such as a field-programmable gate array (FPGA) configured to perform any of the method implementations described herein or any portion thereof.

[0063] UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, UE 106 may be configured to communicate using, for example, CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD), LTE / Advanced LTE, or 5G NR using a single shared radio component and / or GSM, LTE, Advanced LTE, or 5G NR using a single shared radio component. The shared radio component may be coupled to a single antenna or to multiple antennas (e.g., for MIMO) for performing wireless communication. Generally, the radio component may include any combination of baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.) or digital processing circuitry (e.g., for digital modulation and other digital processing). Similarly, the radio component may use the aforementioned hardware to implement one or more receive chains and transmit chains. For example, UE 106 may share one or more portions of the receive chain and / or transmit chain among multiple wireless communication technologies (such as those discussed above).

[0064] In some implementations, UE 106 may include independent transmit and / or receive chains (e.g., including independent antennas and other radio components) for each wireless communication protocol configured to communicate therewith. As another possibility, UE 106 may include one or more radio components shared among multiple wireless communication protocols, as well as one or more radio components uniquely used by a single wireless communication protocol. For example, UE 106 may include shared radio components for communication using either LTE or 5G NR (or LTE or 1xRTT, or LTE or GSM), and separate radio components for communication using each of Wi-Fi and Bluetooth. Other configurations are also possible.

[0065] Figure 2 Block diagram of a base station Figure 2 Example block diagrams of base station 102 according to some implementation schemes are shown. It should be noted that... Figure 2 The base station shown is merely one example of a possible base station. As illustrated, base station 102 may include processor 204, which executes program instructions for base station 102. Processor 204 may also be coupled to memory management unit (MMU) 240, which may be configured to receive addresses from processor 204 and translate those addresses into locations in memory (e.g., memory 260 and read-only memory (ROM) 250) or into other circuitry or devices.

[0066] Base station 102 may include at least one network port 270. Network port 270 may be configured to couple to a telephone network and provide access to multiple devices, such as UE device 106, as described above in Figure 1 and... Figure 2 Access to the telephone network described in the text.

[0067] Network port 270 (or an additional network port) may also be configured, or alternatively configured, to couple to a cellular network, such as the core network of a cellular service provider. The core network may provide mobility-related services and / or other services to multiple devices, such as UE device 106. In some cases, network port 270 may be coupled to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., in other UE devices served by a cellular service provider).

[0068] In some implementations, base station 102 may be a next-generation base station, such as a 5G New Radio (5G NR) base station, or a “gNB”. In such implementations, base station 102 may be connected to a legacy evolved packet core (EPC) network and / or to an NR core (NRC) network. Furthermore, base station 102 may be considered a 5G NR cell and may include one or more transition and receive points (TRPs). Additionally, UEs capable of operating according to 5G NR may be connected to one or more TRPs within one or more gNBs.

[0069] Base station 102 may include at least one antenna 234, and may include multiple antennas. At least one antenna 234 may be configured to operate as a wireless transceiver and may also be configured to communicate with UE device 106 via radio component 230. Antenna 234 communicates with radio component 230 via communication link 232. Communication link 232 may be a receive link, a transmit link, or both. Radio component 230 may be configured to communicate via various wireless communication standards, including but not limited to 5G NR, LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, etc.

[0070] Base station 102 can be configured to perform wireless communication using multiple wireless communication standards. In some instances, base station 102 may include multiple radio components that enable base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, base station 102 may include an LTE radio component for performing communication according to LTE and a 5G NR radio component for performing communication according to 5G NR. In this case, base station 102 may be able to operate as both an LTE base station and a 5G NR base station. As another possibility, base station 102 may include a multimode radio component capable of performing communication according to any of multiple wireless communication technologies (e.g., 5G NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0071] As further described herein, BS 102 may include hardware and software components for implementing or supporting specific implementations of the features described herein. The processor 204 of base station 102 may be configured, for example, to implement or support some or all of the methods described herein by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, processor 204 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array), or as an ASIC (Application-Specific Integrated Circuit), or a combination thereof. Alternatively (or further), in conjunction with one or more of other components 230, 232, 234, 240, 250, 260, 270, the processor 204 of BS 102 may be configured to implement or support some or all of the features described herein.

[0072] Furthermore, as described herein, processor 204 may comprise one or more processing elements. In other words, one or more processing elements may be included in processor 204. Therefore, processor 204 may include one or more integrated circuits (ICs) configured to perform the functions of processor 204. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 204.

[0073] Furthermore, as described herein, radio component 230 may comprise one or more processing elements. In other words, one or more processing elements may be included in radio component 230. Therefore, radio component 230 may include one or more integrated circuits (ICs) configured to perform the functions of radio component 230. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of radio component 230.

[0074] In some implementations, the base station or gNB 102 and / or its processor 204 may be able to and configured to: determine one or more candidate CUs for user equipment (UE) 106 at a source centralized unit (CU) of the gNB; transmit a handover request from the source CU of the gNB to one or more candidate CUs; ​​receive a handover request acknowledgment at the source CU of the gNB from one or more candidate CUs, the handover request acknowledgment containing information about candidate distributed units (DUs) coupled to one or more candidate CUs to form a list of candidate DUs; assign an index to the candidate DUs coupled to one or more candidate CUs at the source CU of the gNB; and encode a radio resource control (RRC) message at the source CU of the gNB, the radio resource control (RRC) message containing the list of candidate DUs coupled to one or more candidate CUs and the assigned index, for transmission to the UE via the source DUs of the gNB.

[0075] Figure 3 Server block diagram Figure 3 Example block diagrams of server 104 according to some implementation schemes are shown. Note that... Figure 3 The server shown is merely one example of a possible server. As illustrated, server 104 may include processor 344 capable of executing program instructions for server 104. Processor 344 may also be coupled to memory management unit (MMU) 374, which may be configured to receive addresses from processor 344 and translate those addresses into locations in memory (e.g., memory 364 and read-only memory (ROM) 354) or into other circuitry or devices.

[0076] Server 104 can be configured to provide network access functionality to multiple devices, such as base station 102 and UE device 106, for example, as further described herein.

[0077] In some implementations, server 104 may be part of a radio access network, such as a 5G New Radio (5G NR) access network. In some implementations, server 104 may be connected to a legacy evolved packet core (EPC) network and / or to an NR core (NRC) network.

[0078] As described herein, server 104 may include hardware and software components for implementing or supporting the implementation of the features described herein. Processor 344 of server 104 may be configured, for example, to implement or support some or all of the methods described herein by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable storage medium). Alternatively, processor 344 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array), or as an ASIC (Application-Specific Integrated Circuit), or a combination thereof. Alternatively (or further), in conjunction with one or more of other components 354, 364, and / or 374, processor 344 of server 104 may be configured to implement or support some or all of the features described herein.

[0079] Furthermore, as described herein, processor 344 may comprise one or more processing elements. In other words, one or more processing elements may be included in processor 344. Therefore, processor 344 may include one or more integrated circuits (ICs) configured to perform the functions of processor 344. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 344.

[0080] Figure 4 : UE block diagram Figure 4 A simplified block diagram of a communication device 106 according to some implementation schemes is shown. Note that... Figure 4 The block diagram of the communication device is merely one example of possible communication devices. According to implementations, communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop computer, notebook computer, or portable computing device), a tablet computer, an unmanned aerial vehicle (UAV), a UAV controller (UAC), and / or a combination of devices, as well as other devices. As shown, communication device 106 may include a set of components 400 configured to perform core functions. For example, this set of components may be implemented as a system-on-a-chip (SOC), which may include portions for various purposes. Alternatively, the set of components 400 may be implemented as individual components or groups of components for various purposes. The set of components 400 may be (e.g., communicatively; directly or indirectly) coupled to various other circuitry of communication device 106.

[0081] For example, communication device 106 may include various types of memory (e.g., including NAND flash memory 410), input / output interfaces such as connector I / F 420 (e.g., for connection to a computer system; docking station; charging station; input devices such as microphone, camera, keyboard; output devices such as speaker; etc.), a display 460 that may be integrated with or external to the communication device 106, and cellular communication circuitry 430 such as for 5G NR, LTE, GSM, etc., and short- to medium-range wireless communication circuitry 429 (e.g., Bluetooth). ™ (and WLAN circuitry). In some embodiments, communication device 106 may include wired communication circuitry (not shown), such as, for example, a network interface card for Ethernet.

[0082] Cellular communication circuitry 430 may be coupled (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 435 and 436 as shown. Short-to-medium-range wireless communication circuitry 429 may also be coupled (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 437 and 438 as shown. Alternatively, short-to-medium-range wireless communication circuitry 429 may be coupled (e.g., communicatively; directly or indirectly) to antennas 435 and 436 in addition to or instead of being coupled to antennas 437 and 438. Short-to-medium-range wireless communication circuitry 429 and / or cellular communication circuitry 430 may include multiple receive chains and / or multiple transmit chains for receiving and / or transmitting multiple spatial streams, such as in a multiple-input multiple-output (MIMO) configuration.

[0083] In some embodiments, as further described below, the cellular communication circuit 430 may include dedicated receive chains for multiple RATs (including and / or coupled to (e.g., communicatively; directly or indirectly) dedicated processors and / or radio components) (e.g., a first receive chain for LTE and a second receive chain for 5G NR). Furthermore, in some embodiments, the cellular communication circuit 430 may include a single transmit chain that can be switched between radio components dedicated to a specific RAT. For example, a first radio component may be dedicated to a first RAT, such as LTE, and may communicate with a dedicated receive chain and a transmit chain shared with additional radio components, such as a second radio component that may be dedicated to a second RAT (e.g., 5G NR) and may communicate with a dedicated receive chain and a shared transmit chain.

[0084] The communication device 106 may also include one or more user interface elements and / or be configured to be used with one or more user interface elements. The user interface elements may include any of a variety of elements, such as a display 460 (which may be a touch screen display), a keyboard (which may be a discrete keyboard or may be implemented as part of a touch screen display), a mouse, a microphone and / or a speaker, one or more cameras, one or more buttons, and / or any of a variety of other elements capable of providing information to the user and / or receiving or interpreting user input.

[0085] The communication device 106 may also include one or more smart cards 445 with SIM (Subscriber Identity Module) functionality, such as one or more UICC (Universal Integrated Circuit Card) cards 445. It should be noted that the term "SIM" or "SIM entity" is intended to include any of various types of SIM implementations or SIM functions, such as one or more UICC cards 445, one or more eUICCs, one or more eSIMs, removable or embedded, etc. In some embodiments, the UE 106 may include at least two SIMs. Each SIM may execute one or more SIM applications and / or otherwise implement SIM functionality. Thus, each SIM may be a single smart card that can be embedded, for example, soldered to a circuit board in the UE 106, or each SIM 410 may be implemented as a removable smart card. Therefore, a SIM may be one or more removable smart cards (such as UICC cards, sometimes referred to as "SIM cards"), and / or SIM 410 may be one or more embedded cards (such as embedded UICCs (eUICCs), sometimes referred to as "eSIMs" or "eSIM cards"). In some implementations (such as when the SIM includes an eUICC), one or more SIMs within the SIM can implement embedded SIM (eSIM) functionality; in such implementations, a single SIM within the SIM can execute multiple SIM applications. Each SIM may include components such as a processor and / or memory; instructions for performing SIM / eSIM functionality may be stored in memory and executed by the processor. In some implementations, UE 106 may include, as needed, a combination of removable smart cards and fixed / non-removable smart cards (such as one or more eUICC cards implementing eSIM functionality). For example, UE 106 may include two embedded SIMs, two removable SIMs, or a combination of one embedded SIM and one removable SIM. Various other SIM configurations are also envisioned.

[0086] As described above, in some implementations, UE 106 may include two or more SIMs. Including two or more SIMs in UE 106 allows UE 106 to support two different phone numbers and allows UE 106 to communicate on two or more corresponding networks. For example, the first SIM may support a first RAT such as LTE, and the second SIM 106 may support a second RAT such as 5G NR. Other specific implementations and RATs are also possible. In some implementations, when UE 106 includes two SIMs, UE 106 may support Dual SIM Dual Standby (DSDA) functionality. DSDA functionality allows UE 106 to connect to two networks simultaneously (and use two different RATs), or allows two connections supported by two different SIMs using the same or different RATs to be maintained simultaneously on the same or different networks. DSDA functionality also allows UE 106 to receive voice calls or data traffic simultaneously on either phone number. In some implementations, voice calls may be packet-switched communications. In other words, voice calls can be received using LTE-based Voice (VoLTE) technology and / or NR-based Voice (VoNR) technology. In some implementations, UE 106 may support Dual SIM Dual Standby (DSDS) functionality. DSDS functionality allows either of the two SIMs in UE 106 to remain in standby while awaiting a voice call and / or data connection. In DSDS, when a call / data connection is established on one SIM, the other SIM is no longer active. In some implementations, DSDx functionality (DSDA or DSDS functionality) can be implemented using a single SIM (e.g., eUICC) that performs multiple SIM applications for different carriers and / or RATs.

[0087] As shown in the figure, the SOC 400 may include a processor 402 and display circuitry 404. The processor executes program instructions for the communication device 106, and the display circuitry performs graphics processing and provides display signals to the display 460. The processor 402 may also be coupled to a memory management unit (MMU) 440 (which may be configured to receive addresses from the processor 402 and translate those addresses into locations in memory (e.g., memory 406, read-only memory (ROM) 450, NAND flash memory 410)) and / or coupled to other circuitry or devices (such as display circuitry 404, short-to-medium range wireless communication circuitry 429, cellular communication circuitry 430, connector I / F 420, and / or display 460). The MMU 440 may be configured to perform memory protection and page table translation or setup. In some embodiments, the MMU 440 may be included as part of the processor 402.

[0088] As described herein, communication device 106 may include hardware and software components for implementing the features described above to communicate a scheduling profile for power saving to the network. For example, processor 402 of communication device 106 may be configured to implement some or all of the features described herein by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable storage medium). Alternatively (or in addition), processor 402 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array) or as an ASIC (Application-Specific Integrated Circuit). Alternatively (or in addition), in conjunction with one or more of other components 400, 404, 406, 410, 420, 429, 430, 440, 445, 450, 460, processor 402 of communication device 106 may be configured to implement some or all of the features described herein.

[0089] Furthermore, as described herein, processor 402 may include one or more processing elements. Therefore, processor 402 may include one or more integrated circuits (ICs) configured to perform the functions of processor 402. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 402.

[0090] Additionally, as described herein, the cellular communication circuit 430 and the short-to-medium-range wireless communication circuit 429 may each include one or more processing elements. In other words, one or more processing elements may be included in the cellular communication circuit 430, and similarly, one or more processing elements may be included in the short-to-medium-range wireless communication circuit 429. Therefore, the cellular communication circuit 430 may include one or more integrated circuits (ICs) configured to perform the functions of the cellular communication circuit 430. Furthermore, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the cellular communication circuit 430. Similarly, the short-to-medium-range wireless communication circuit 429 may include one or more ICs configured to perform the functions of the short-to-medium-range wireless communication circuit 429. Furthermore, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the short-to-medium-range wireless communication circuit 429.

[0091] Figure 5 Block diagram of cellular communication circuit Figure 5 Simplified block diagrams of cellular communication circuits according to some implementation schemes are shown. Note that... Figure 5The block diagram of the cellular communication circuit is merely one example of a possible cellular communication circuit. According to the implementation, the cellular communication circuit 530 (which may be the cellular communication circuit 430) may be included in a communication device such as the communication device 106 described above. As noted above, among other devices, the communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop computer, notebook computer, or portable computing device), a tablet computer, and / or a combination of these devices.

[0092] The cellular communication circuit 530 may (e.g., communicatively; directly or indirectly) be coupled to one or more antennas, such as ( Figure 4 Antennas 435a-b and 436 are shown in the diagram. In some embodiments, cellular communication circuitry 530 may include dedicated receive chains for various RATs (including and / or coupled to (e.g., communicatively ground; directly or indirectly) dedicated processors and / or radio components) (e.g., a first receive chain for LTE and a second receive chain for 5G NR). For example, as... Figure 5 As shown, the cellular communication circuit 530 may include a modem 510 and a modem 520. The modem 510 may be configured for communication according to a first RAT (e.g., such as LTE or LTE-A), and the modem 520 may be configured for communication according to a second RAT (e.g., such as 5G NR).

[0093] As shown, modem 510 may include one or more processors 512 and memory 516 communicating with processors 512. Modem 510 may communicate with radio frequency (RF) front end 530. RF front end 530 may include circuitry for transmitting and receiving radio signals. For example, RF front end 530 may include receiver circuitry (RX) 532 and transmitter circuitry (TX) 534. In some embodiments, receiver circuitry 532 may communicate with downlink (DL) front end 550, which may include circuitry for receiving radio signals via antenna 335a.

[0094] Similarly, modem 520 may include one or more processors 522 and memory 526 communicating with processor 522. Modem 520 may communicate with RF front end 540. RF front end 540 may include circuitry for transmitting and receiving radio signals. For example, RF front end 540 may include receiving circuitry 542 and transmitting circuitry 544. In some embodiments, receiving circuitry 542 may communicate with DL front end 560, which may include circuitry for receiving radio signals via antenna 335b.

[0095] In some implementations, switch 570 may couple transmitting circuitry 534 to uplink (UL) front-end 572. Additionally, switch 570 may couple transmitting circuitry 544 to UL front-end 572. UL front-end 572 may include circuitry for transmitting radio signals via antenna 336. Therefore, when cellular communication circuitry 530 receives an instruction to transmit according to a first RAT (e.g., supported by modem 510), switch 570 may be switched to a first state allowing modem 510 to transmit signals according to the first RAT (e.g., via a transmission chain including transmitting circuitry 534 and UL front-end 572). Similarly, when cellular communication circuitry 530 receives an instruction to transmit according to a second RAT (e.g., supported by modem 520), switch 570 may be switched to a second state allowing modem 520 to transmit signals according to the second RAT (e.g., via a transmission chain including transmitting circuitry 544 and UL front-end 572).

[0096] As described herein, modem 510 may include hardware and software components for implementing the features described above or for UL data used in time-division multiplexing NSA NR operation, as well as various other techniques described herein. For example, processor 512 may be configured to implement some or all of the features described herein by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable storage medium). Alternatively (or in addition), processor 512 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array) or as an ASIC (Application-Specific Integrated Circuit). Alternatively (or in addition), processor 512 may be configured to implement some or all of the features described herein by combining one or more of other components 530, 532, 534, 550, 570, 572, 335a, 335b, and 336.

[0097] Furthermore, as described herein, processor 512 may include one or more processing elements. Therefore, processor 512 may include one or more integrated circuits (ICs) configured to perform the functions of processor 512. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 512.

[0098] For example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium), processor 522 may be configured to implement some or all of the features described herein. Alternatively (or in addition), processor 522 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array) or as an ASIC (Application-Specific Integrated Circuit). Alternatively (or in addition), in conjunction with one or more of other components 540, 542, 544, 550, 570, 572, 335a, 335b, and 336, processor 522 may be configured to implement some or all of the features described herein.

[0099] Furthermore, as described herein, processor 522 may include one or more processing elements. Therefore, processor 522 may include one or more integrated circuits (ICs) configured to perform the functions of processor 522. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 522.

[0100] Figure 6 Block diagram of the baseband processor architecture for UE Figure 6 Example components of device 600 according to some implementation schemes are illustrated. It should be noted that... Figure 6 The device described is merely one example of a possible system, and the features of this disclosure can be implemented in any type of UE as needed.

[0101] In some embodiments, device 600 may include application circuitry 602, baseband circuitry 604, radio frequency (RF) circuitry 606, front-end module (FEM) circuitry 608, one or more antennas 610, and power management circuitry (PMC) 612 (at least coupled together as shown). Components of the illustrated device 600 may be included in UE 106 or a RAN node. In some embodiments, device 600 may include fewer components (e.g., the RAN node may not utilize application circuitry 602, but instead include a processor / controller to process IP data received from the EPC). In some embodiments, device 600 may include additional components such as, for example, memory / storage devices, displays, cameras, sensors, or input / output (I / O) interfaces. In other embodiments, the components described below may be included in more than one device (e.g., the circuitry may be individually included in more than one device for a cloud-RAN (C-RAN) specific implementation).

[0102] Application circuitry 602 may include one or more application processors. For example, application circuitry 602 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The one or more processors may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). These processors may be coupled to or may include memory / storage devices and may be configured to execute instructions stored in the memory / storage device to enable various applications or operating systems to run on device 600. In some embodiments, the processor of application circuitry 602 may process IP data packets received from the EPC.

[0103] Baseband circuitry 604 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. Baseband circuitry 604 may include one or more baseband processors or control logic components to process baseband signals received from the receive signal path of RF circuitry 606 and generate baseband signals for the transmit signal path of RF circuitry 606. Baseband processing circuitry 604 may interact with application circuitry 602 to generate and process baseband signals and control the operation of RF circuitry 606. For example, in some embodiments, baseband circuitry 604 may include a third-generation (3G) baseband processor 604A, a fourth-generation (4G) baseband processor 604B, a fifth-generation (5G) baseband processor 604C, or other existing, under development, or future generations of baseband processors 604D (e.g., second-generation (2G), sixth-generation (6G), etc.). Baseband circuitry 604 (e.g., one or more of baseband processors 604A-D) may process various radio control functions that enable communication with one or more radio networks via RF circuitry 606. In other embodiments, some or all of the functions of the baseband processors 604A-D may be included in modules stored in memory 604G and executed via a central processing unit (CPU) 604E. Radio control functions may include, but are not limited to, signal modulation / demodulation, encoding / decoding, and radio frequency shifting. In some embodiments, the modulation / demodulation circuitry of the baseband circuitry 604 may include Fast Fourier Transform (FFT), pre-decoding, or constellation mapping / demapping functionality. In some embodiments, the encoding / decoding circuitry of the baseband circuitry 604 may include convolution, tail-biting convolution, turbo, Viterbi, or low-density parity-check (LDPC) encoder / decoder functionality. Implementations of the modulation / demodulation and encoder / decoder functions are not limited to these examples, and other suitable functions may be included in other embodiments.

[0104] In some embodiments, the baseband circuitry 604 may include one or more audio digital signal processors (“DSPs”) 604F. The audio DSP 604F may include elements for compression / decompression and echo cancellation, and in other embodiments may include other suitable processing elements. In some embodiments, components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on the same circuit board. In some embodiments, some or all of the components of the baseband circuitry 604 and the application circuitry 602 may be implemented together, for example, on a system-on-a-chip (SOC).

[0105] In some implementations, baseband circuit 604 can provide communication compatible with one or more radio technologies. For example, in some implementations, baseband circuit 604 can support communication with the Evolved Universal Terrestrial Radio Access Network (EUTRAN) or other Wireless Metropolitan Area Networks (WMAN), Wireless Local Area Networks (WLAN), or Wireless Personal Area Networks (WPAN). Implementations in which baseband circuit 604 is configured to support radio communication with more than one radio protocol may be referred to as multimode baseband circuits.

[0106] RF circuit 606 enables communication with a wireless network via a non-solid medium using modulated electromagnetic radiation. In various embodiments, RF circuit 606 may include switches, filters, amplifiers, etc., to facilitate communication with the wireless network. RF circuit 606 may include a receive signal path that includes circuitry for down-converting the RF signal received from FEM circuit 608 and providing a baseband signal to baseband circuit 604. RF circuit 606 may also include a transmit signal path that includes circuitry for up-converting the baseband signal provided by baseband circuit 604 and providing an RF output signal for transmission to FEM circuit 608.

[0107] In some embodiments, the receive signal path of RF circuit 606 may include mixer circuit 606a, amplifier circuit 606b, and filter circuit 606c. In some embodiments, the transmit signal path of RF circuit 606 may include filter circuit 606c and mixer circuit 606a. RF circuit 606 may also include synthesizer circuit 606d for synthesizing frequencies used by mixer circuit 606a in both the receive and transmit signal paths. In some embodiments, mixer circuit 606a in the receive signal path may be configured to down-convert the RF signal received from FEM circuit 608 based on the synthesized frequency provided by synthesizer circuit 606d. Amplifier circuit 606b may be configured to amplify the down-converted signal, and filter circuit 606c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signal to generate an output baseband signal. The output baseband signal may be provided to baseband circuit 604 for further processing. In some implementations, these output baseband signals may be zero-frequency baseband signals, but this is not necessary. In some implementations, the mixer circuit 606a in the receiving signal path may include a passive mixer, but the scope of the implementations is not limited in this respect.

[0108] In some implementations, the mixer circuit 606a of the transmit signal path may be configured to up-convert the input baseband signal based on the synthesis frequency provided by the synthesizer circuit 606d to generate an RF output signal for the FEM circuit 608. The baseband signal may be provided by the baseband circuit 604 and may be filtered by the filter circuit 606c.

[0109] In some embodiments, the mixer circuit 606a for the receive signal path and the mixer circuit 606a for the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and quadrature upconversion, respectively. In some embodiments, the mixer circuit 606a for the receive signal path and the mixer circuit 606a for the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuit 606a for the receive signal path and the mixer circuit 606a for the transmit signal path may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuit 606a for the receive signal path and the mixer circuit 606a for the transmit signal path may be configured for superheterodyne operation.

[0110] In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, but the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, RF circuit 606 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry, and baseband circuit 604 may include a digital baseband interface for communicating with RF circuit 606.

[0111] In some dual-mode implementations, separate radio IC circuits may be provided to process signals for each spectrum, but the scope of the implementation is not limited in this respect.

[0112] In some implementations, synthesizer circuit 606d may be a fractional-N synthesizer or a fractional-N / N+1 synthesizer, but the scope of implementations is not limited in this respect, as other types of frequency synthesizers may also be suitable. For example, synthesizer circuit 606d may be a Δ-∑ synthesizer, a frequency multiplier, or a synthesizer including a phase-locked loop with a frequency divider.

[0113] Synthesizer circuit 606d can be configured to synthesize an output frequency based on a frequency input and a divider control input for use by mixer circuit 606a of RF circuit 606. In some embodiments, synthesizer circuit 606d may be a fractional N / N+1 synthesizer.

[0114] In some implementations, the frequency input may be provided by a voltage-controlled oscillator (VCO), but this is not necessary. The divider control input may be provided by the baseband circuitry 604 or the application processor 602 according to the desired output frequency. In some implementations, the divider control input (e.g., N) may be determined from a lookup table based on the channel indicated by the application processor 602.

[0115] The synthesizer circuit 606d of the RF circuit 606 may include a frequency divider, a delay-locked loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the frequency divider may be a dual-mode divider (DMD), and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by N or N+1 (e.g., based on carry) to provide a fractional division ratio. In some example embodiments, the DLL may include a cascaded, tunable delay element, a phase detector, a charge pump, and a set of D-type flip-flops. In these embodiments, the delay elements may be configured to divide the VCO cycle into Nd equal phase groups, where Nd is the number of delay elements in the delay line. Thus, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0116] In some embodiments, synthesizer circuitry 606d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and frequency divider circuitry to generate multiple signals having multiple different phases relative to each other at the carrier frequency. In some embodiments, the output frequency may be the LO frequency (fLO). In some embodiments, RF circuitry 606 may include an IQ / polarity converter.

[0117] FEM circuit 608 may include a receive signal path, which may include circuitry configured to operate on RF signals received from one or more antennas 610, amplify the received signals, and provide an amplified version of the received signals to RF circuit 606 for further processing. FEM circuit 608 may also include a transmit signal path, which may include circuitry configured to amplify transmit signals provided by RF circuit 606 for transmission by one or more of the one or more antennas 610. In various embodiments, amplification via the transmit or receive signal path may be performed only in RF circuit 606, only in FEM 608, or in both RF circuit 606 and FEM 608.

[0118] In some embodiments, FEM circuit 608 may include a TX / RX switch for switching between transmit and receive mode operation. The FEM circuit may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuit may include an LNA for amplifying the received RF signal and providing the amplified received RF signal as an output (e.g., provided to RF circuit 606). The transmit signal path of FEM circuit 608 may include a power amplifier (PA) for amplifying (e.g., provided by RF circuit 606) the input RF signal; and one or more filters for generating an RF signal for subsequent transmission (e.g., through one or more antennas in one or more antennas 610).

[0119] In some implementations, the PMC 612 manages the power supplied to the baseband circuitry 604. Specifically, the PMC 612 controls power selection, voltage scaling, battery charging, or DC-DC conversion. The PMC 612 is typically included when the device 600 can be battery powered, for example, when the device is included in a UE. The PMC 612 can improve power conversion efficiency while providing the desired specific implementation size and thermal characteristics.

[0120] Although Figure 6A PMC 612 is shown coupled only to the baseband circuit 604, but in other embodiments, the PMC 612 may be coupled additionally or alternatively to other components such as, but not limited to, the application circuit 602, the RF circuit 606, or the FEM 608, and perform similar power management operations for these other components.

[0121] In some implementations, the PMC 612 may control or otherwise become part of various power-saving mechanisms of the device 600. For example, if the device 600 is in the Radio Resource Control_Connected (RRC_Connected) state, where the device is still connected to the RAN node because it expects to receive traffic immediately, it may enter a state called Discontinuous Receive Mode (DRX) after a period of inactivity. During this state, the device 600 may power down for short intervals, thereby saving power.

[0122] If there is no data traffic activity during the extended period, device 600 can transition to the RRC_Idle state, in which the device disconnects from the network and does not perform operations such as channel quality feedback or handover. Device 600 enters a very low power state and performs paging, in which the device periodically wakes up again to listen to the network, and then powers off again. Device 600 may be unable to receive data in this state, and to receive data, it will transition back to the RRC_Connected state.

[0123] An additional power-saving mode renders the device unusable for a period exceeding the paging interval (from seconds to hours). During this time, the device is completely unconnected to the network and may be completely powered off. Any data transmitted during this period will incur significant latency, which is assumed to be acceptable.

[0124] The processor of application circuit 602 and the processor of baseband circuit 604 can be used to execute elements of one or more instances of the protocol stack. For example, the processor of baseband circuit 604 can be used individually or in combination to perform layer 3, layer 2, or layer 1 functions, while the processor of application circuit 604 can utilize data received from these layers (e.g., packet data) and further perform layer 4 functions (e.g., transmit communication protocol (TCP) and user datagram protocol (UDP) layers). As mentioned herein, layer 3 (L3) may include the Radio Resource Control (RRC) layer, which will be described in further detail below. As mentioned herein, layer 2 (L2) may include the Media Access Control (MAC) layer, the Radio Link Control (RLC) layer, and the Packet Data Convergence Protocol (PDCP) layer, which will be described in further detail below. As mentioned herein, layer 1 (L1) may include the physical (PHY) layer of the UE / RAN node, which will be described in further detail below. Therefore, baseband circuit 604 can be used to encode messages for transmission between the UE and gNB, or to decode messages received between the UE and gNB.

[0125] Figure 7 Block diagram of the baseband circuit interface Figure 7 Example interfaces of baseband circuits according to some implementation schemes are illustrated. Note that... Figure 7 The baseband circuit is merely one example of a possible circuit, and the features of this disclosure can be implemented in any of various systems as needed.

[0126] As discussed above, Figure 6 The baseband circuit 604 may include processors 604A-604E and a memory 604G utilized by the processors. Each of the processors 604A-604E may respectively include a memory interface 704A-704E for transferring / receiving data to / from the memory 604G.

[0127] The baseband circuit 604 may further include: one or more interfaces for communicatively coupling to other circuits / devices, such as a memory interface 712 (e.g., an interface for transferring data to / receiving data from a memory external to the baseband circuit 604); and an application circuit interface 714 (e.g., for...). Figure 6 The application circuit 602 is an interface for transmitting data / receiving data from the application circuit; the RF circuit interface 716 (e.g., for transmitting data to / from the application circuit) Figure 6 RF circuit 606 is an interface for transmitting / receiving data from / from the RF circuit; wireless hardware connectivity interface 718 (e.g., for connecting to / from near field communication (NFC) components, Bluetooth). ® Components (e.g., Bluetooth) ® Low power consumption, Wi-Fi ®Interfaces for transmitting / receiving data from components and other communication components); and power management interface 720 (e.g., an interface for transmitting or receiving power or control signals to / from the PMC 612).

[0128] Figure 8 Control plane protocol stack Figure 8 This is an example of a control plane protocol stack according to some implementation schemes. In this implementation scheme, control plane 800 is shown as a communication protocol stack between UE 106a (or alternatively, UE 106b), RAN node 611 (or alternatively, RAN node 612) and Mobility Management Entity (MME) 621.

[0129] PHY layer 801 can transmit or receive information used by MAC layer 802 through one or more air interfaces. PHY layer 801 can further perform link adaptive or adaptive modulation and decoding (AMC), power control, cell search (e.g., for initial synchronization and handover purposes), and other measurements used by higher layers (such as RRC layer 805). PHY layer 801 can also further perform: error detection of the transport channel, forward error correction (FEC) decoding / decoding of the transport channel, modulation / demodulation of the physical channel, interleaving, rate matching, mapping to the physical channel, and multiple-input multiple-output (MIMO) antenna processing.

[0130] MAC layer 802 can perform the following: mapping between logical channels and transport channels, multiplexing MAC service data units (SDUs) from one or more logical channels onto a transport block (TB) to be delivered to the PHY via the transport channel, demultiplexing MAC SDUs from a transport block (TB) delivered from the PHY via the transport channel onto one or more logical channels, multiplexing MAC SDUs onto a TB, scheduling information reporting, error correction via Hybrid Automatic Repeat Request (HARQ), and logical channel prioritization.

[0131] RLC layer 803 can operate in multiple modes, including Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). RLC layer 803 can perform the transmission of higher-layer protocol data units (PDUs), error correction via Automatic Repeat Request (ARQ) for AM data transmission, and concatenation, segmentation, and reassembly of RLC SDUs for UM and AM data transmission. RLC layer 803 can also re-segment RLC data PDUs used for AM data transmission, reorder RLC data PDUs used for UM and AM data transmission, detect duplicate data used for UM and AM data transmission, discard RLC SDUs used for UM and AM data transmission, detect protocol errors used for AM data transmission, and perform RLC re-establishment.

[0132] PDCP layer 804 can perform header compression and decompression of IP data, maintain PDCP sequence numbers (SNs), perform sequential delivery of upper-layer PDUs during lower-layer re-establishment, eliminate duplication of lower-layer SDUs during lower-layer re-establishment for radio bearers mapped on RLC AM, encrypt and decrypt control plane data, perform integrity protection and integrity verification of control plane data, control timer-based data discarding, and perform security operations (e.g., encryption, decryption, integrity protection, integrity verification, etc.).

[0133] The main services and functions of RRC layer 805 may include broadcasting system information (e.g., included in the Master Information Block (MIB) or System Information Block (SIB) related to the Non-Access Stratum (NAS), broadcasting system information related to the Access Stratum (AS), paging, establishment, maintenance, and release of RRC connections between the UE and E-UTRAN (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), establishment, configuration, maintenance, and release of point-to-point radio bearers, security functions including key management, mobility between Radio Access Technologies (RATs), and measurement configuration for UE measurement reporting. The MIB and SIB may include one or more Information Elements (IEs), each of which may include a separate data field or data structure.

[0134] UE 601 and RAN node 611 can use the Uu interface (e.g., the LTE-Uu interface) to exchange control plane data via a protocol stack including PHY layer 801, MAC layer 802, RLC layer 803, PDCP layer 804 and RRC layer 805.

[0135] The Non-Access Stratum (NAS) protocol 806 forms the highest layer of the control plane between UE 601 and MME 621. NAS protocol 806 supports the mobility and session management procedures of UE 601 to establish and maintain IP connectivity between UE 601 and P-GW 623.

[0136] The S1 Application Protocol (S1-AP) layer 815 supports the functions of the S1 interface and includes the Basic Procedure (EP). The EP is the interaction unit between RAN node 1010 and CN 1020. S1-AP layer services can include two sets: UE-associated services and non-UE-associated services. These services perform functions including, but not limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UE capability indication, mobility, NAS signaling transmission, RAN Information Management (RIM), and configuration transmission.

[0137] The Flow Control Transmission Protocol (SCTP) layer (optionally referred to as the SCTP / IP layer) 814 may, in part, rely on the IP protocol supported by the IP layer 813 to ensure reliable delivery of signaling messages between the RAN node 611 and the MME 621. The L2 layer 812 and the L1 layer 811 may refer to the communication links (e.g., wired or wireless) used by the RAN node and the MME to exchange information.

[0138] RAN node 611 and MME 621 can exchange control plane data via the S1-MME interface through a protocol stack including L1 layer 811, L2 layer 812, IP layer 813, SCTP layer 814 and S1-AP layer 815.

[0139] Figure 9 User plane protocol stack Figure 9 This is an example of a user plane protocol stack according to some implementation schemes. In this implementation, user plane 900 is shown as a communication protocol stack between UE 106A (or alternatively, UE 106B or 106N), RAN node 611 (or alternatively, RAN node 612), S-GW 622, and P-GW 623. User plane 900 may utilize at least some of the same protocol layers as control plane 800. For example, UE 601 and RAN node 611 may exchange user plane data via a protocol stack including PHY layer 801, MAC layer 802, RLC layer 803, and PDCP layer 804 using a Uu interface (e.g., LTE-Uu interface).

[0140] The General Packet Radio Service (GPRS) tunneling protocol for the user plane (GTP-U) layer 904 can be used to carry user data within the GPRS core network and between the radio access network and the core network. For example, the transmitted user data can be packets in any of the IPv4, IPv6, or PPP formats. The UDP and IP Security (UDP / IP) layer 903 provides checksums for data integrity, port numbers for addressing different functions at the source and destination, and encryption and authentication for selected data streams. RAN node 611 and S-GW 622 can exchange user plane data using the S1-U interface via a protocol stack including L1 layer 811, L2 layer 812, UDP / IP layer 903, and GTP-U layer 904. S-GW 622 and P-GW 623 can exchange user plane data using the S5 / S8a interface via a protocol stack including L1 layer 811, L2 layer 812, UDP / IP layer 903, and GTP-U layer 904. (As described above...) Figure 8 The NAS protocol discussed here supports the mobility and session management process of UE 106 to establish and maintain IP 913 connectivity between UE 106 and P-GW 623.

[0141] Figure 10 Core network Figure 10 Example architectures of system 1000, including core network (CN) 1020, are illustrated according to various implementation schemes. CN 1020 may be the core network of a 5G system (which may be referred to as 5GC). System 1000 is shown to include UE 1001, which may be the same as or similar to UE 106A, 106B, or 106N previously discussed; (R)AN 102, which may be the same as or similar to BS 102A or 102N previously discussed; and data network (DN) 1003, which may be, for example, operator services, Internet access, or third-party services; and CN 1020. CN 1020 may include multiple network functions, including Authentication Server Function (AUSF) 1022; Access and Mobility Management Function (AMF) 1021; Session Management Function (SMF) 1024; Network Exposure Function (NEF) 1023; Policy Control Function (PCF) 1026; Network Repository Function (NRF) 1025; Unified Data Management (UDM) 1027; Application Function (AF) 1028; User Plane Function (UPF) 1002; and Network Slice Selection Function (NSSF) 1029. In some cases, these network functions may be implemented as virtualization software-based functions / services.

[0142] UPF 1002 can act as an anchor point for mobility within and between RATs, an external Packet Data Unit (PDU) session point interconnected with DN 1003, and a branch point supporting multihomed PDU sessions. A PDU session is a logical connection between the UE and the DN. UPF 1002 can also perform packet routing and forwarding, packet inspection, user plane portion of policy rules, lawful packet interception (user plane (UP) collection), traffic usage reporting, quality of service (QoS) processing on the user plane (e.g., packet filtering, gating, UL / DL rate enforcement), uplink traffic verification (e.g., Service Data Stream (SDF) to QoS stream mapping), transport level packet marking in uplink and downlink, and downlink packet buffering and downlink data notification triggering. UPF 1002 may include an uplink classifier to support traffic flow routing to the data network, and DN 1003 may represent various network operator services, Internet access, or third-party services. DN 1003 may include or be similar to the previously discussed application server 430. UPF 1002 can interact with SMF1024 via the N4 reference point between SMF 1021 and UPF 1002.

[0143] AUSF 1022 can store authentication data for UE 1001 and handle authentication-related functionality. AUSF 1022 can facilitate a common authentication framework for various access types. AUSF 1022 can communicate with AMF 1021 via the N12 reference point between AMF 1021 and AUSF 1022; and can communicate with UDM 1027 via the N13 reference point between UDM 1027 and AUSF 1022. Additionally, AUSF 1022 can present an interface based on Nausf services.

[0144] AMF 1021 is responsible for registration management (e.g., registering UE 1001, etc.), connection management, reachability management, mobility management, lawful interception of AMF-related events, and access authentication and authorization. AMF 1021 can be the termination point of the N11 reference point between AMF 1021 and SMF 1024. AMF 1021 provides transport for SM messages between UE 1001 and SMF 1024 and acts as a transparent proxy for routing SM messages. AMF 1021 can also be used between UE 1001 and SMSF (… Figure 10 AMF 1021 provides transmission of Short Message Service (SMS) messages between (not shown). AMF 1021 can act as a Security Anchor Function (SEAF), which may include interaction with AUSF 1022 and UE 1001, and reception of an intermediate key established due to the UE 1001 authentication process. In the case of authentication using the Universal User Identity Module (USIM), AMF 1021 may retrieve security material from AUSF 1022. AMF 1021 may also include a Security Context Management (SCM) function, which receives a key from the SEAF for deriving a network-specific access key. Furthermore, AMF 1021 may be the termination point of the RAN Control Plane (CP) interface, which may include or be the N2 reference point between (R)AN 1010 and AMF 1021, and AMF 1021 may be the termination point of NAS (N1) signaling, performing NAS encryption and integrity protection.

[0145] AMF 1021 can also support NAS signaling with UE 1001 via a Non-3GPP Interoperability Function (N3IWF) interface. N3IWF can be used to provide access to untrusted entities. N3IWF can be the termination point of the N2 interface between the control plane (R)AN 1010 and AMF 1021, and can be the termination point of the N3 reference point between the user plane (R)AN 1010 and UPF 1002. Therefore, AMF 1021 can process N2 signaling for PDU sessions from SMF 1024 and AMF 1021, encapsulate / decapsulate packets for IPSec and N3 tunneling, mark N3 user plane packets in the uplink, and perform QoS corresponding to the N3 packet markings, while taking into account the QoS requirements associated with such markings received via N2. The N3IWF can also relay uplink and downlink control plane non-access stratum (NAS) signaling between UE 1001 and AMF 1021 via the N1 reference point between UE 1001 and AMF 1021, and relay uplink and downlink user plane packets between UE 1001 and UPF 1002. The N3IWF also provides a mechanism for establishing an Internet Protocol Security (IPsec) tunnel using UE 1001. AMF 1021 can present an interface based on Namf services and can be the N14 reference point between two AMF 1021s, as well as the AMF 1021 and the 5G Equipment Identity Register (5G-EIR). Figure 10 The endpoint of the N17 reference point (not shown).

[0146] UE 1001 may need to register with AMF 1021 to receive network services. Registration Management (RM) is used to register or deregister UE 1001 with the network (e.g., AMF 1021) and to establish a UE context in the network (e.g., AMF 1021). UF 1001 can operate in RM-REGISTERED or RM-DEREGISTERED states. In RM-DEREGISTERED state, UE 1001 does not register with the network, and the UE context in AMF 1021 does not maintain valid location or routing information for UE 1001, therefore AMF 1021 cannot reach UE 1001. In RM-REGISTERED state, UE 1001 registers with the network, and the UE context in AMF 1021 can maintain valid location or routing information for UE 1001, therefore AMF 1021 can reach UE 1001. In RM-REGISTERED state, UE 1001 can perform mobility registration update procedures, periodic registration update procedures triggered by the expiration of periodic update timers (e.g., notifying the network that UE 1001 is still active), and registration update procedures to update UE capability information or renegotiate protocol parameters with the network, etc.

[0147] The AMF 1021 can store one or more RM contexts for UE 1001, where each RM context is associated with a specific access to the network. The RM context can be a data structure, database object, etc., indicating or storing registration status and periodic update timers, particularly for each access type. The AMF 1021 can also store 5GC Mobility Management (MM) contexts that are the same as or similar to the Evolved Packet Services (EPS) Mobility Management (E) MM contexts discussed earlier. In various implementations, the AMF 1021 can store UE 1001's CE Mode B restriction parameters in the associated MM context or Registration Management (RM) context. The AMF 1021 can also derive values ​​from UE usage setting parameters already stored in the UE context (and / or MM / RM context) when needed.

[0148] Connection Management (CM) can be used to establish and release signaling connections between UE 1001 and AMF 1021 via the N1 interface. Signaling connections are used to enable NAS signaling exchange between UE 1001 and CN 1020, and include signaling connections between the UE and AN (e.g., RRC connections for non-3GPP access or UE-N3IWF connections) and N2 connections between the AN (e.g., AN 1010) and AMF 1021 for UE 1001. UE 1001 can operate in one of two CM states (CM-IDLE mode or CM-CONNECTED mode). When UE 1001 operates in CM-IDLE state / mode, UE 1001 may not have a NAS signaling connection established with AMF 1021 via the N1 interface, and (R)AN 1010 signaling connections (e.g., N2 and / or N3 connections) may exist for UE 1001. When UE 1001 operates in CM-CONNECTED state / mode, UE 1001 may have a NAS signaling connection established with AMF 1021 via the N1 interface, and may have a (R)AN 1010 signaling connection (e.g., N2 and / or N3 connection) for UE 1001. Establishing an N2 connection between (R)AN 1010 and AMF 1021 allows UE 1001 to transition from CM-IDLE mode to CM-CONNECTED mode, and UE 1001 can transition from CM-CONNECTED mode to CM-IDLE mode when the N2 signaling between (R)AN 1010 and AMF 1021 is released.

[0149] SMF 1024 is responsible for Session Management (SM), session establishment, modification, and publication (including tunnel maintenance between UPF and AN nodes); UE IP address allocation and management (including optional authorization); selection and control of UP functions; configuration of UPF traffic redirection to route traffic to the correct destination; termination of interfaces toward policy control functions; policy enforcement and QoS control portions; lawful interception (for SM events and interfaces with the LI system); termination of the SM portion of NAS messages; downlink data notification; initiation of AN-specific SM information transmitted to the AN via N2 through AMF; and determination of the SSC mode of the session. SM may refer to the management of PDU sessions, and a PDU session or "session" may refer to the PDU connectivity service that provides or enables PDU exchange between UE 1001, identified by the Data Network Name (DNN), and Data Network (DN) 1003. A PDU session can be established upon request from UE 1001, modified upon request from both UE 1001 and CN 1020, and released upon request from both UE 1001 and CN 1020 using NAS SM signaling exchanged via the N1 reference point between UE 1001 and SMF1024. Upon request from the application server, CN 1020 can trigger a specific application within UE 1001. In response to receiving a trigger message, UE 1001 can pass the trigger message (or relevant portions / information of the trigger message) to one or more identified applications within UE 1001. The identified application within UE 1001 can establish a PDU session to a specific data network name (DNN). SMF 1024 can check whether the UE 1001 request matches the user subscription information associated with UE 1001. In this regard, SMF 1024 can retrieve and / or request to receive update notifications regarding SMF1024 level subscription data from UDM 1027.

[0150] The SMF 1024 may include the following roaming functionalities: handling local execution to apply QoS SLAB Virtual Public Land Mobile Network (VPLMN); charging data collection and charging interface (VPLMN); lawful interception (for SM events and interfaces with the LI system, in the VPLMN); and support for interaction with external DNs to transmit signaling for PDU session authorization / authentication via external DNs. In roaming scenarios, an N16 reference point between two SMF 1024s may be included in System 1000, which may be located between another SMF 1024 in the visited network and an SMF 1024 in the home network. Additionally, the SMF 1024 may present an interface based on NSMF services.

[0151] The NEF 1023 provides components for securely exposing services and capabilities provided by 3GPP network functions to third parties, internal exposure / re-exposure, application functions (e.g., AF 1028), edge computing, or fog computing systems. In such implementations, the NEF 1023 can authenticate, authorize, and / or restrict AFS. The NEF 1023 can also translate information exchanged with AF 1028 and information exchanged with internal network functions. For example, the NEF 1023 can translate between AF service identifiers and internal SCC information. The NEF 1023 can also receive information from other network functions (NFs) based on their exposure capabilities. This information can be stored as structured data at the NEF 1023 or stored at a data storage NF using a standardized interface. The stored information can then be re-exposed by the NEF 1023 to other NFs and AFs, and / or used for other purposes such as analysis. Additionally, the NEF 1023 can present an interface based on Nnef services.

[0152] The NRF 1025 supports service discovery, receiving NF discovery requests from NF instances and providing information about discovered NF instances to them. The NRF 1025 also maintains information about available NF instances and the services they support. As used herein, terms such as "instantiation" can refer to the creation of an instance, and "instance" can refer to the concrete occurrence of an object, which may occur, for example, during the execution of program code. Additionally, the NRF 1025 can present an interface based on Nnrf services.

[0153] The PCF 1026 can provide policy rules to control plane functions for enforcement and supports a unified policy framework to manage network behavior. The PCF 1026 can also implement a front-end (FE) to access subscription information related to policy decisions in the UDR of the UDM 1027. The PCF 1026 can communicate with the AMF 1021 via an N15 reference point, which can include the PCF 1026 in the visited network and the AMF 1021 in roaming scenarios. PCF 1026 can communicate with AF 1028 via the NS reference point between PCF 1026 and AF 1028; and communicate with SMF 1024 via the N7 reference point between PCF 1026 and SMF 1024. System 1000 and / or CN 1020 may also include an N24 reference point between PCF 1026 (in the home network) and PCF 1026 in the visited network. In addition, PCF 1026 may present an interface based on NPCF services.

[0154] UDM 1027 can process subscription-related information to support network entities in handling communication sessions and can store subscription data for UE 1001. For example, subscription data can be communicated between UDM 1027 and AMF 1021 via an NS reference point between UDM 1027 and AMF. UDM 1027 may include two parts: Application FE and UDR ( Figure 10 (FE and UDR are not shown). The UDR may store subscription data and policy data of UDM 1027 and PCF 1026, and / or structured data for exposure of NEF 1023, as well as application data (including PFD for application detection, application request information of multiple UE 1001s). An interface based on the Nadr service may be presented by UDR 221 to allow UDM 1027, PCF 1026, and NEF 1023 to access a specific set of stored data, and to read, update (e.g., add, modify), delete, and subscribe to notifications of relevant data changes in the UDR. The UDM may include UDM-FE, which is responsible for handling credentials, location management, subscription management, etc. Several different front-ends may serve the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing, user identification processing, access authorization, registration / mobility management, and subscription management. The UDR may interact with SMF 1024 via the N10 reference point between UDM 1027 and SMF 1024. The UDM 1027 also supports SMS management, with SMS-FE implementing similar application logic as previously discussed. Additionally, the UDM 1027 can present an interface based on Nudm services.

[0155] AF 1028 can provide application influence on traffic routing, provide access to the NCE, and interact with the policy framework for policy control. The NCE can be a mechanism allowing CN 1020 and AF 1028 to provide information to each other via NEF 1023, which can be used in edge computing implementations. In such implementations, network operators and third-party services can be hosted near the UE 1001 access point to achieve efficient service delivery through reduced end-to-end latency and load on the transport network. For edge computing implementations, 5GC can select UPF 1002 near UE 1001 and perform traffic redirection from UPF 502 to ON 1003 via the N6 interface. This can be based on UE subscription data, UE location, and information provided by AF 1028. In this way, AF 1028 can influence UPF (re)selection and traffic routing. Based on operator deployment, when AF 1028 is considered a trusted entity, the network operator can allow AF 1028 to interact directly with the relevant NF. In addition, the AF 1028 can present an interface based on Naf services.

[0156] NSSF 1029 can select a set of network slice instances to serve UE 501. If needed, NSSF 1029 can also determine the allowed network slice selection assistance information (NSSAI) and the mapping to the subscribed individual NSSAI (S-NSSAI). NSSF 1029 can also determine the set of AMFs, or a list of candidate AMFs 1021, for serving UE 1001 based on appropriate configuration and possibly by querying NRF 1025. The selection of a set of network slice instances for UE 1001 can be triggered by AMF 1021 registered with UE 1001 interacting with NSSF 1029, which can result in a change to AMF 1021. NSSF 1029 can interact with AMF 1021 via the N22 reference point between AMF 1021 and NSSF 1029; and via the N31 reference point (…). Figure 10 (Not shown) communicates with another NSSF 1029 in the visited network. Additionally, the NSSF 1029 can present an interface based on the Nnssf service.

[0157] As previously discussed, CN 1020 may include a Short Message Service Function (SMSF), which is responsible for SMS subscription checks and verification, as well as relaying SM messages to and / or from UE 1001 or other entities such as SMS-GMSC / IWMSC / SMS routers. SMS may also interact with AMF 1021 and UDM 1027 to notify UE 1001 of its availability for SMS transmission (e.g., setting a UE unreachable flag and notifying UDM 1027 when UE 1001 is available for SMS).

[0158] CN 1020 may also include Figure 10 Other elements not shown include data storage systems / architecture, 5G-EIR, Secure Edge Protection Agent (SEPP), etc. Data storage systems may include Structured Data Storage Network Function (SDSF), Unstructured Data Storage Function (UDSF), etc. Any network function (NF) can be transmitted via any NF and UDSF ( Figure 10 The N18 reference point (not shown) is used to store unstructured data in or retrieve unstructured data from the UDSF (e.g., UE context). Individual NFs can share a UDSF to store their respective unstructured data, or each NF can have its own UDSF located at or near its location. Additionally, the UDSF can present an interface based on Nudsf services (…). Figure 10(Not shown). 5G-EIR can be an NF that checks the status of a Permanent Equipment Identifier (PEI) to determine whether a specific piece of equipment / entity should be blacklisted from the network; and SEPP can be a non-transparent agent that performs topology hiding, message filtering, and policing on the control plane interface between PLMNs.

[0159] Furthermore, there can be more reference points and / or service-based interfaces between NF services; however, for clarity, Figure 10 These interfaces and reference points are omitted. In one example, CN 1020 may include an Nx interface, which is an inter-CN interface between the Mobility Management Entity (MME) and AMF 1021 to enable interoperability between CN 1020 and CNs in the 4G system. Other example interfaces / reference points may include an interface based on N5G-EIR services presented by 5G-EIR, reference point N27 between the NRF in the visited network and the NRF in the home network; and reference point N31 between the NSSF in the visited network and the NSSF in the home network.

[0160] Inter-cube mobility (LTM) In 3GPP Release 19, one objective is to specify support for Layer 1 (L1) / Layer 2 (L2) triggered mobility (LTM) between CUs. One scenario that might be expected to be supported is when the CU acts as the primary node (MN) when dual connectivity (DC) is not configured. Another scenario that might be expected to be supported is when a new radio DC (NR-DC) is configured and the CU acts as the secondary node (SN) with the primary cell group (MCG) remaining unchanged. Yet another scenario that might be expected to be supported is when the NR-DC is configured, the CU acts as the MN, and the secondary cell group (SCG) remains unchanged or the SCG is released. The scenario of configuring LTM in both the MCG and SCG can be excluded. 3GPP Release 19 may specify support for subsequent LTM mobility procedures to avoid Radio Resource Control (RRC) configuration between cell handovers according to 3GPP Release 18 LTM.

[0161] Measurement-related enhancements (RAN2, RAN1) for supporting LTM are applicable to both intra-CU MCG / SCG LTM and inter-CU MCG / SCG LTM. The embodiments described herein disclose message transmission for identifying distributed units (DUs) controlled intra-CU or inter-CU, associating DUs with identifiers, and communicating potential DUs available for LTM to the UE as candidates for the UE to switch to during the LTM process.

[0162] Legacy CU handover security dynamics—For inter-CU (or even intra-CU where a gNB expects a security context change), the source gNB can provide the target gNB with the current UE security capabilities and security keys, such as KgNB (Kng-ran). The KgNB can be derived from either of the following: horizontal derive—based on the previous KgNB (when the source gNB does not have an NH / NCC pair); or vertical derive—based on the NH / NCC pair that the source gNB has. The NCC can be provided to the target gNB. The source gNB can use the KgNB as a security key to derive the Kng-ran. The target gNB can use the Kng-ran as the KgNB key and can prepare the target configuration. The NCC used is also included with the target configuration. The UE can derive the security key based on the NCC. If the NCCs are the same, they can be derived using the horizontal key. If the NCCs are different, the UE can derive the NH until the NCCs match (incrementing each time). After the handover is complete, the target gNB can notify the AMF using PATH SWITCH completion. The AMF can create a new set of NH / NCCs and provide it to the target gNB.

[0163] Legacy L3 CU handover may involve: the security key to be changed; the PDCP to be restored and the new security context to be applied; the radio link control (RLC) to be reset; the old RLC context to be cleared and the RLC to be reset to its initial state; and the MAC to be reset for each transmit / receive point (TRP). Security key "refreshing" is even allowed within the CU, which results in a security context change and thus leads to associated PDCP restoration / RLC and MAC resets.

[0164] Figure 11 Deployment via Xn Figure 11 Example diagrams of intra-CU and inter-CU LTM cell handover 1100 according to some implementation schemes are provided. From the UE's perspective, there may be a mixture of intra-CU and inter-CU Physical Cell Identifiers (PCIs). From the UE's perspective, the UE can see cells (PCIs) from the same CU (intra-CU) or different CUs (inter-CU). One CU-m can interface with another CU-n via Xn interface 1110. Xn interface 1110 can be a point-to-point interface between two Next Generation Radio Access Network (NG-RAN) nodes.

[0165] Figure 12 Deployed via Ng Figure 12 Example diagrams of intra-CU and inter-CU LTM cell handover 1200 according to some implementation schemes are provided. Similarly, from the UE's perspective, there may be a mixture of intra-CU and inter-CU Physical Cell Identifiers (PCIs). CU-m can be transmitted via the Ng interface through the core network 1020 ( Figure 10 The Access and Mobility Management Function (AMF) 1210 in the 5G core network interfaces with another CU-n. The AMF 1210 can be a control plane function in the 5G core network that handles connectivity and mobility management tasks. Each CU can connect to one or more DUs via an F1 interface. Each DU can have one or more PCIs.

[0166] For intra-CU LTM, the gNB-CU (e.g., the source CU) can act as a coordinator. The gNB-CU can, for example, obtain candidate PCI information from the DU using the UE_CONTEXT_SETUP_REQUEST / RESPONSE message. The gNB-CU can, for example, provide a variety of configurations to the source DU using the UE_CONTEXT_MODIFICATION_REQUEST / RESPONSE message. The gNB-CU can merge the network RRC configuration and then provide that configuration to the UE using the source DU (e.g., using the DL RRC MESSAGE TRANSFER message). For inter-CU, a central coordinator may also be required.

[0167] Physical layer configuration can be "masked" under the gNB-CU. In legacy operation, beamforming, channel state information (CSI), and other physical layer information may not be shared outside the CU. The Xn HANDOVER_REQUEST / ACK message can be used only to exchange UE-specific context information.

[0168] LTM configuration provides a design solution for handling inter-CU LTM handover during network node switching and how to configure the UE. UE behavior during LTM handover can be based on the previous RRC configuration and the presence / absence of the LTM handover MAC CE (inter-CU). However, additional UE behavior during LTM handover can be obtained through additional signaling. For example, it is necessary to determine how the UE will learn whether the LTM handover is within a DU or between DUs; or within a CU or between CUs. Additional signaling can clarify the UE behavior during LTM handover.

[0169] Figure 13 A unified interface for UEs Figure 13 An example of signaling 1300 for inter-CU LTM handover according to some implementation schemes is illustrated. A candidate set of LTM cells may be provided to UE 106, wherein the candidate set of LTM cells is provided to UE 106 as a list. In step 1: the source central unit (CU) may determine which target or candidate CUs (CU1, CU2) are useful to UE 106.

[0170] In step 2: The source CU can obtain LTM configuration information from these candidate CUs (CU1, CU2). On one hand, the source CU can use the HANDOVER_REQUEST message to trigger a request for LTM configuration information. On the other hand, each candidate CU (CU1, CU2) can request information about candidate DUs from the target or candidate distributed unit (DU) (DU10, DU11, DU20) controlled by the corresponding CU. The candidate CU (CU1, CU2) can determine from which DUs it requests information. The candidate CU (CU1, CU2) can use the UECONTEXT_SETUP_REQUEST / RESPONSE message to request and / or collect configuration information from the candidate DUs (DU10, DU11, DU20). On the other hand, each candidate CU (CU1, CU2) can configure the network into a list of candidate DUs (DU10, DU11, DU20). On the other hand, each candidate CU (CU1, CU2) can respond to the source CU in HANDOVER_REQUEST_ACKNOWLEDGE, which contains a list of candidate or target DUs (DU10, DU11, DU20) coupled to the candidate CU (CU1, CU2).

[0171] In step 3: The source CU can sort the list of candidate cells for each target or candidate DU (DU10, DU11, DU20) from each candidate CU (CU1, CU2). The source CU can assign candidate cell indices and ensure that there are no duplicate indices among the candidate DUs (DU10, DU11, DU20) from all candidate CUs (CU1, CU2).

[0172] In step 4: The source CU can use the UE_CONTEXT_MODIFICATION procedure to notify the source DU of the list of candidate cells and the candidate cell index.

[0173] In step 5: The source CU can prepare an RRC message containing the configuration of the LTM candidate, and transmit the RRC message to the UE 106 via the source DU using a DL RRC MESSAGETRANSFER message. The source CU can receive confirmation from the source DU that the RRC message to the UE has been transmitted.

[0174] In some examples, the apparatus of the next-generation node B (gNB) 102 may include one or more processors 204 coupled to memory 260. Processor 204 may be configured to: determine one or more candidate CUs (CU1, CU2) for user equipment (UE) 106 at a source centralized unit (CU) of gNB 102. Processor 204 may be configured to: transmit handover requests from the source CU of gNB 102 to one or more candidate CUs (CU1, CU2). Processor 204 may be configured to: receive handover request acknowledgments from one or more candidate CUs (CU1, CU2) at the source CU of gNB 102, the handover request acknowledgments containing information about candidate distributed units (DUs) coupled to each of the one or more candidate CUs, to form a list of candidate DUs (DU10, DU11, DU20). Processor 204 may be configured to: assign indices to the candidate DUs (DU10, DU11, DU20) coupled to one or more candidate CUs (CU1, CU2) at the source CU of gNB 102. Processor 204 can be configured to encode a Radio Resource Control (RRC) message at the source CU of gNB 102, the RRC message containing a list and assigned indexes of candidate DUs (DU10, DU11, DU20) coupled to one or more candidate CUs (CU1, CU2), for transmission to UE 106 via the source DU of gNB 102. In one example, the RRC message may be a DL RRC MESSAGE TRANSFER message. However, other types of RRC messages may also be used to convey the list of candidate DUs and their assigned indexes to the UE.

[0175] On the other hand, one or more candidate CUs (CU1, CU2) may include CUs.

[0176] On the other hand, the processor 204 can be configured to sort a list of candidate DUs (DU10, DU11, DU20) coupled to one or more candidate CUs (CU1, CU2) at the source CU of gNB 102.

[0177] On the other hand, processor 204 can be configured to: transfer a list and assigned indexes of candidate DUs (DU10, DU11, DU20) coupled to one or more candidate CUs (CU1, CU2) from a source CU of gNB 102 to a source DU of gNB 102. Processor 204 can be configured to: use a UE context modification (UE_CONTEXT_MODIFICATION) procedure to transfer the assigned indexes and assigned indexes of candidate DUs (DU10, DU11, DU20) coupled to one or more candidate CUs (CU1, CU2) from a source CU of gNB 102 to a source DU of gNB 102. Processor 204 can be configured to: receive at the source CU of gNB 102 an acknowledgment from the source DU that the list and assigned indexes of candidate DUs (DU10, DU11, DU20) have been conveyed to the UE.

[0178] On the other hand, the processor 204 can be configured to transmit a handover request and receive a handover request confirmation via the Xn interface 1110 between the source CU and one or more candidate CUs (CU1, CU2).

[0179] On the other hand, processor 204 can be configured to receive handover request acknowledgments from one or more candidate CUs (CU1, CU2) at the source CU of gNB 102. At least one of the one or more candidate CUs can be configured to: transmit a request in a UE context establishment request (UE CONTEXT_SETUP_REQUEST) message for Layer 1 / Layer 2 triggered mobility (LTM) information for each candidate DU (DU10, DU11, DU20) controlled by at least one candidate CU; or transmit a request for LTM information to selected DUs (DU10, DU11, DU20) controlled by at least one candidate CU; and transmit a list of candidate DUs (DU10, DU11, DU20) containing LTM information to the source CU in a handover request acknowledgment (HANDOVER_REQUEST_ACKNOWLEDGEMENT) message.

[0180] Figure 14 Flowchart of the method for inter-CU LTM Figure 14 A flowchart illustrating an example of a method 1400 for inter-layer 1 / layer 2 mobility (LTM) triggered between central units (CUs) according to some implementation schemes is shown. Figure 14 The methods shown can also be used in conjunction with any of the systems, methods, or apparatuses illustrated in the figures, as well as other devices. In various embodiments, some of the method elements shown may be performed concurrently in a different order than those shown, or may be omitted. Additional method elements may also be performed as needed.

[0181] According to one embodiment, a method 1400 for Layer 1 / Layer 2 triggered mobility (LTM) between central units (CUs) at a next-generation node B (gNB) is disclosed. Method 1400 may include: determining (1410) one or more candidate CUs for user equipment (UE) at a source CU of the gNB. Method 1400 may include: transmitting a handover request from the source CU of the gNB (1420) to one or more candidate CUs. Method 1400 may include: receiving (1430) a handover request confirmation from one or more candidate CUs at the source CU of the gNB, the handover request confirmation containing information about candidate distributed units (DUs) coupled to one or more candidate CUs to form a list of candidate DUs. Method 1400 may include: assigning (1440) an index to the candidate DUs coupled to one or more candidate CUs at the source CU of the gNB. Method 1400 may include: encoding (1450) a radio resource control (RRC) message at a source CU of the gNB, the radio resource control (RRC) message containing a list of candidate DUs coupled to one or more candidate CUs and an assigned index, for transmission to the UE via the source DU of the gNB.

[0182] On the other hand, method 1400 may also include: one or more candidate CUs including CUs.

[0183] On the other hand, method 1400 may further include: sorting a list of candidate DUs coupled to one or more candidate CUs at the source CU of the gNB.

[0184] In another aspect, method 1400 may further include: transmitting a list of candidate DUs coupled to one or more candidate CUs and their assigned indices from a source CU of the gNB to a source DU of the gNB. Method 1400 may further include: using a UE context modification (UE_CONTEXT_MODIFICATION) procedure, transmitting the assigned indices of the candidate DUs coupled to one or more candidate CUs from a source CU of the gNB to a source DU of the gNB. Method 1400 may further include: receiving, at the source CU of the gNB, confirmation from the source DU of the list of candidate DUs and their assigned indices that have been communicated to the UE.

[0185] In another aspect, method 1400 may further include: transmitting a handover request and receiving a handover request acknowledgment via the Xn interface between the source CU and one or more candidate CUs. Method 1400 may further include: receiving a handover request acknowledgment from one or more candidate CUs at the source CU of the gNB. At least one of the one or more candidate CUs is configured to: transmit a request in a UE context establishment request (UE CONTEXT_SETUP_REQUEST) message for Layer 1 / Layer 2 triggered mobility (LTM) information from each candidate DU controlled by at least one candidate CU; or transmit a request for LTM information to a selected DU controlled by at least one candidate CU; and transmit a list of candidate DUs containing LTM information to the source CU in a handover request acknowledgment (HANDOVER_REQUEST_ACKNOWLEDGEMENT) message.

[0186] Figure 15 A unified interface for UEs with NG (Next Generation) capabilities Figure 15 An example of signaling 1500 for inter-CU LTM handover according to some implementation schemes is illustrated. A candidate set of LTM cells may be provided to UE 106, wherein the candidate set of LTM cells is provided to UE 106 as a list. In step 1: the source CU can determine which candidate CUs (CU1, CU2) are useful to UE 106.

[0187] Step 2: The source CU can obtain LTM configuration information from these target or candidate CUs (CU2) via the Ng interface using the AMF (AMF2). Alternatively, the source CU can trigger a request for LTM configuration information using the NG CONTEXT MODIFICATION message. Alternatively, the AMF (AMF2) can request LTM candidates from each candidate CU (CU2) using the NG CONTEXT MODIFICATION message. Alternatively, each candidate CU (CU2) can request information about target or candidate DUs (DU20) from the DUs it controls. The candidate CU (CU2) can determine from which DUs (DU20) to request information. The candidate CU (CU2) can use the UECONTEXT_SETUP_REQUEST / RESPONSE message to request and / or collect DU configuration information. Alternatively, each candidate CU (CU2) can configure the network into a list of DUs (DU20) controlled by the candidate CU. On the other hand, each candidate CU (CU2) can respond to the source CU using a list of candidate DUs (CU20) controlled by the candidate CU (CU2) in the NG CONTEXT MODIFICATION ACK message.

[0188] In step 3: The source CU can sort the list of candidate cells for each candidate DU (DU10, DU11, DU20) from each candidate CU (CU1, CU2). On the other hand, the source CU can assign a candidate cell index to each DU and ensure that there are no duplicate indices among the DUs (DU10, DU11, DU20) of all candidate CUs from candidate CU (CU1, CU2).

[0189] In step 4: The source CU can use the UE_CONTEXT_MODIFICATION procedure to notify the source DU of the list of candidate cells and the candidate cell index.

[0190] In step 5: The source CU can receive confirmation from the source DU regarding the success of the procedure. The source CU can prepare an RRC message containing the configuration of the LTM candidate and can transmit the RRC message to UE 106 via the source DU using the DL RRC MESSAGE TRANSFER message.

[0191] UE 106 can determine the NCC, instead of letting the AMF determine it. UE selection of the NCC allows all three participants (UE, gNB, and AMF) to synchronize with the next key to be used. The gNB may still not be aware of the NH of other gNBs, thus maintaining security requirements. Interface changes between gNB and AMF (N2 interface) and between gNBs (Xn interface) may be required, as well as RRC changes in the UE interface.

[0192] In some examples, processor 204 may also be configured to transmit handover requests and receive handover request acknowledgments via the Ng interface between each CU (CU2) and the network's Access and Mobility Management Function (AMF). Processor 204 may also be configured to receive handover request acknowledgments from one or more candidate CUs (CU2) at the source CU of gNB 102. The AMF (AMF2) may be configured to transmit a request for Layer 1 / Layer 2 triggered mobility (LTM) information to each candidate CU (CU2) in an Ng context modification message. Processor 204 may also be configured to receive handover request acknowledgments from one or more candidate CUs (CU2) at the source CU of gNB 102. At least one candidate CU (CU2) among one or more candidate CUs can be configured to: transmit a request in a UE CONTEXT_SETUP_REQUEST / RESPONSE message for Layer 1 / Layer 2 triggered mobility (LTM) information from each of one or more candidate DUs (DU20) controlled by at least one candidate CU (CU2); or transmit a request for LTM information to a selected DU (DU20) controlled by at least one candidate CU (CU2); and transmit a list of candidate DUs (DU20) containing LTM information to the source CU in an Ng CONTEXT MODIFICATION ACKNOWLEDGEMENT message.

[0193] In some examples, method 1400 may further include: transmitting a handover request and receiving a handover request acknowledgment via the Ng interface between each CU and the network's Access and Mobility Management Function (AMF). Method 1400 may further include: receiving a handover request acknowledgment from one or more candidate CUs at the source CU of the gNB. The AMF may be configured to: transmit a request for Layer 1 / Layer 2 triggered mobility (LTM) information to each candidate CU in an Ng context modification message. Method 1400 may further include: receiving a handover request acknowledgment from one or more candidate CUs at the source CU of the gNB. At least one of the one or more candidate CUs can be configured to: transmit a request in a UE CONTEXT_SETUP_REQUEST / RESPONSE message for Layer 1 / Layer 2 triggered mobility (LTM) information for each candidate DU controlled by at least one candidate CU; or transmit a request for LTM information to a selected DU controlled by at least one candidate CU; and transmit a list of candidate DUs containing LTM information to the source CU in an NG CONTEXT MODIFICATION ACKNOWLEDGEMENT message.

[0194] Figure 16 and Figure 17 The unified interface facing the UE at the UE location. Figure 16 and Figure 17 Examples of MAC CE 1600 and 1700 for transmitting information according to some implementation schemes are illustrated. The UE can store candidate cells as a list. The UE can not distinguish between candidate cells controlled by inter-CU (e.g., DU) and candidate cells controlled by intra-CU.

[0195] A network node may send MAC CE 1600 or 1700 to the UE. The UE can obtain information from MAC CE 1600 or 1700. MAC CE 1600 or 1700 may include a MAC CE type indication field 1604. The MAC CE type indication field 1604 indicates the type of MAC CE. In the illustrated example, the MAC CE type indication field 1604 indicates that MAC CE 1600 or 1700 is used for LTM cell handover. Therefore, the UE can use the information in MAC CE 1600 or 1700 to prepare for LTM cell handover. For example, MAC CE 1600 or 1700 may include a candidate cell configuration field 1606. The candidate cell configuration field 1606 indicates the target cell that the UE should hand over to. MAC CE 1600 or 1700 may also include other information, such as a Transmission Configuration Indicator (TCI) configuration field 1608, which includes TCI configuration information.

[0196] refer to Figure 16 When an LTM cell handover occurs, MAC CE 1600 can provide information about whether the handover is between or within a CU. For example, MAC CE 1600 may include an inter-CU LTM information field 1612. In the absence of inter-CU MAC CE information, the UE may follow the 3GPP Rel-18 logic of performing a Radio Link Control (RLC) reset or a MAC reset only.

[0197] In some examples, processor 204 may be configured to encode a Media Access Control-Control Element (MAC CE) at the source DU of gNB 102, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with inter-CU indication or intra-CU indication.

[0198] In some examples, method 1400 may further include: encoding a media access control-control element (MAC CE) at the source DU of the gNB, the media access control-control element (MAC CE) indicating a Layer 1 / Layer 2 triggered mobility (LTM) cell handover with inter-CU indication or intra-CU indication.

[0199] refer to Figure 17 The MAC CE 1700 may include additional indexes to carry information related to the next hop chain counter (NCC). For example, the MAC CE 1700 may include an inter-CU LTM NCC information field 1712. The presence of an NCC in the MAC CE 1700 indicates that it is an inter-CU cell handover. No new fields may be needed. The presence of an NCC (which can be used for security context changes) may now also mean that it is an inter-CU cell handover. In the absence of a MAC CE NCC, the UE may follow the 3GPP Rel-18 logic of performing an RLC reset or a MAC-only reset. The MAC CE 1700 may also include other information, such as a random access channel (RACH) configuration field 1710, which includes RACH configuration information.

[0200] In some examples, processor 204 may be configured to encode a media access control-control element (MAC CE) at the source DU of gNB 102, the media access control-control element (MAC CE) indicating a layer 1 / layer 2 triggered mobility (LTM) cell handover with a next-hop parameter (NH) NH chain counter (NCC) indicating inter-CU cell handover.

[0201] In some examples, method 1400 may further include: encoding a media access control-control element (MAC CE) at the source DU of the gNB, the media access control-control element (MAC CE) indicating a layer 1 / layer 2 triggered mobility (LTM) cell handover with a next-hop parameter (NH) NH chain counter (NCC) indicating inter-CU cell handover.

[0202] In any of the above situations, the UE can re-establish the PDCP context (i.e., perform PDCP recovery) and reset the RLC and MAC.

[0203] Figure 18 : Processing based on each CU Figure 18 An example of signaling 1800 for inter-CU LTM handover is illustrated according to some implementation schemes. The process can be performed on a per-CU basis. In some cases (such as inter-vendor CU scenarios), the gNB-CU may not be exposed to configuration aspects of the DU controlled by the target / candidate CU. In step 1: the source CU can determine which candidate CUs are useful to the UE.

[0204] Step 2: The source CU can obtain LTM configuration information from these candidate CUs. On one hand, the source CU can use the HANDOVER_REQUEST message to trigger a request for LTM configuration information. On the other hand, each candidate CU can request information about candidate DUs from the DUs it controls. The candidate CU can determine from which DUs it requests information. The candidate CU can use the UE CONTEXT_SETUP_REQUEST / RESPONSE message to request and / or collect DU configurations. On another hand, each candidate CU can construct a list of DUs based on the network configuration. On yet another hand, each candidate CU can respond to the source CU using the list of candidate DUs controlled by the candidate CU in the HANDOVER_REQUEST_ACKNOWLEDGE message.

[0205] In step 3, the source CU can sort the list of candidate cells, where each DU resides within its CU container. Alternatively, the source CU can assign candidate cell indices, but these indices are coupled to each CU. The source CU can ensure that there are no duplicate indices within DUs from each candidate CU; however, such restrictions may not exist between candidate CUs. Alternatively, the source CU can assign an index to each CU.

[0206] In step 4: The source CU may, for example, use the UE_CONTEXT_MODIFICATION procedure to notify the source DU of the list of candidate cells and the candidate cell index.

[0207] In step 5: The source CU can receive an acknowledgment from the source DU. The source CU can prepare an RRC message containing the configuration of the LTM candidate, and can transmit the RRC message to the UE via the source DU using the DL RRC MESSAGE TRANSFER message.

[0208] UE 106 can determine the NCC, instead of letting the AMF determine it. UE selection of the NCC allows all three participants (UE, gNB, and AMF) to synchronize with the next key to be used. The gNB may still not be aware of the NH of other gNBs, thus maintaining security requirements. Interface changes between gNB and AMF (N2 interface) and between gNBs (Xn interface) may be required, as well as RRC changes in the UE interface.

[0209] In some examples, processor 204 may be configured to: sort a list of candidate DUs coupled to one or more candidate CUs within a corresponding CU container at the source CU of gNB 102. Processor 204 may be configured to: assign indices to one or more candidate DUs coupled to one or more candidate CUs within a corresponding CU container at the source CU of gNB 102. Processor 204 may be configured to: assign indices to one or more candidate CUs at the source CU of gNB 102.

[0210] In some examples, method 1400 may further include: sorting a list of candidate DUs coupled to one or more candidate CUs within a corresponding CU container at the source CU of the gNB. Method 1400 may further include: assigning an index to one or more candidate DUs coupled to a candidate CU within a corresponding CU container at the source CU of the gNB. The method may also include: assigning an index to one or more candidate CUs at the source CU of the gNB.

[0211] Figure 19 : Processing based on each CU Figure 19 An example of a MAC CE 1900 for transmitting information according to some implementation schemes is illustrated. This method can be the same as in cases involving the AMF (Ng interface). The UE can store candidate cells as a list; however, the UE can maintain this list for each candidate CU. The distinction between UEs within a CU container and between DUs can follow Rel-18 logic.

[0212] For LTM handovers across CUs, when an LTM cell handover occurs, the MAC CE can provide information about whether the LTM cell handover is an inter-CU or intra-CU handover, including the CU index. For example, MAC CE 1600 may include the inter-CU LTM information field 1912. If no inter-CU MAC CE information is available, the UE may follow the 3GPP Rel-18 logic of performing an RLC reset or a MAC reset only. However, if the MAC CE does not indicate an inter-CU handover, it is assumed that the LTM candidate cell index is intra-CU (i.e., within the CU), as this index can be the same across CUs. Otherwise, the MAC CE may indicate the CU container index. The UE may re-establish the Packet Data Convergence Protocol (PDCP) context (i.e., perform PDCP recovery) and may reset the RLC and MAC.

[0213] In some examples, processor 204 may be configured to encode a Media Access Control-Control Element (MAC CE) at the source DU of gNB 102, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with inter-CU or intra-CU indications containing CU indices.

[0214] In some examples, method 1400 may include: encoding a media access control-control element (MACCE) at the source DU of the gNB, the media access control-control element (MACCE) indicating a Layer 1 / Layer 2 triggered mobility (LTM) cell handover with an inter-CU or intra-CU indication containing a CU index.

[0215] Figure 20 and Figure 21 Hybrid approach based on each CU Based on some examples per CU, a list of candidate LTM cells can be provided to the UE, where the cell index includes information about the parent CU. The UE can store candidate cells as a list, and can do so without distinguishing between CUs, but each candidate DU can be associated with information about its parent CU.

[0216] In some examples, processor 204 may be configured to assign an index at the source CU of the gNB to a candidate DU coupled to one or more candidate CUs using information about the corresponding candidate CU.

[0217] In some examples, method 1400 may also include: at the source CU of the gNB, using information about the corresponding candidate CU, assigning an index to the candidate DU coupled to one or more candidate CUs.

[0218] Based on some examples, all cells within a cell can have a unique index, even when a parent CU exists. For LTM handover, the UE can deduce whether it is between CUs or within a CU based on the index of the candidate cell in the LTM cell handover MAC CE. The CU index in the MAC CE may not be necessary.

[0219] Figure 20 An example of an ASN.1 code 2000 for network configuration of SIB1 is shown according to some implementation schemes. The MAC CE LTM structure may remain unchanged. Fields or information elements (IEs) such as ltm-parentCU-Index-r19 may be introduced. The index can provide the number of LTM CUs for configuring the UE for 3GPP version 19 (r19).

[0220] In some examples, all candidate DUs in one or more candidate DUs may have a unique index.

[0221] Figure 21 An example of a MAC CE 2100 for transmitting information according to some implementation schemes is illustrated. According to some examples based on each CU, a list of candidate LTM cells can be provided to the UE, where the cell index includes information about the parent CU. The UE can store the candidate cells as a list, and can do not distinguish between CUs, but each candidate DU can have information about its parent CU.

[0222] As illustrated in some examples, even when a parent CU exists, all cells within a cell may not have a unique index across CUs. For LTM handover, the LTM MAC CE may also include a parent CU index. Each CU can reuse the same index within its candidate cells, and the UE can distinguish between them because the MAC CE will have a CU index, and the CU index provides context about which DU within that CU. For example, the MAC CE 1600 may include an inter-CU LTM information field 2112. Based on the CU index in the LTM cell handover MAC CE (or the presence of a CU index), the UE can deduce whether it is an inter-CU or intra-CU cell handover. If the CU index does not exist, the LTM candidate cell index may belong to the current CU. As illustrated in some examples, LTM-CandidateId-r18 may not be unique and may be linked to ltm-parentCU-Index-r19.

[0223] In some examples, processor 204 may also be configured to encode a Media Access Control-Control Element (MAC CE) at the source DU of gNB 102, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover between CUs having a CU index. Alternatively, the CU index may also include an LTM parent CU index (ltm-parentCU-r19).

[0224] In some examples, method 1400 may further include encoding a Media Access Control-Control Element (MAC CE) at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover between CUs having a CU index. In another aspect, the CU index may also include an LTM parent CU index (ltm-parentCU-r19).

[0225] Figure 22 LTM triggered by a UE without LTM MAC CE Figure 22 An example of LTM handover 2200 according to some implementation schemes is illustrated. According to some examples, when the UE is configured with a parent CU as described herein, a unique index as described herein can be used. The CU index may not be used in the LTM MAC CE, and an LTM MAC CE may not exist. The UE can store candidate cells as a list, and may not distinguish between inter-CU and intra-CU handover. LTM handover can be triggered by the UE (without MAC CE). If the indices of the source LTM candidate and the target LTM candidate cause a change in the CU index, the UE may assume inter-CU LTM. Otherwise, it is intra-CU LTM. If it is inter-CU (as derived from the logic above), the UE can use the next set of security keys.

[0226] Examples of LTM handovers could include: 4 to 1 (for inter-CU); 4 to 2 (for intra-CU); any handover from 6 could be inter-CU (since only 6 is a candidate in a CU with ID 4); and similarly, a handover from ID 1 (CU ID 7).

[0227] Embodiments of this disclosure may be implemented in any of a variety of forms. For example, some embodiments may be implemented as computer-implemented methods, computer-readable storage media, or computer systems. Other embodiments may be implemented using one or more custom-designed hardware devices such as ASICs. Other embodiments may be implemented using one or more programmable hardware elements such as FPGAs.

[0228] In some embodiments, a non-transitory computer-readable storage medium may be configured to store program instructions and / or data, wherein, if executed by a computer system, the program instructions cause the computer system to perform a method, such as any method embodiment of the method embodiments described herein, or any combination of method embodiments described herein, or any subset or combination of any such subset of any method embodiments described herein.

[0229] In some implementations, the device (e.g., UE 106) may be configured to include a processor (or a set of processors) and a memory medium, wherein the memory medium stores program instructions, and the processor is configured to read from and execute the program instructions from the memory medium, wherein the program instructions are executable to implement any of the various method implementations described herein (or any combination of method implementations described herein, or any subset of any method implementations described herein, or any combination of such subsets). The device may be implemented in any of the various forms.

[0230] By interpreting each message / signal X received by the user equipment (UE) in the downlink as a message / signal X sent by the base station, and interpreting each message / signal Y sent by the UE in the uplink as a message / signal Y received by the base station, any of the methods described herein for operating the UE can serve as the basis for a corresponding method for operating the base station.

[0231] Although the above embodiments have been described in considerable detail, many variations and modifications will become apparent to those skilled in the art once the above disclosure is fully understood. It is intended that the following claims be construed as encompassing all such variations and modifications.

Claims

1. An apparatus for a next-generation node B (gNB), the apparatus comprising: One or more processors, said one or more processors coupled to memory, said one or more processors being configured to: One or more candidate CUs for user equipment (UE) are determined at the source centralized unit (CU) of the gNB; The handover request is transmitted from the source CU of the gNB to the one or more candidate CUs; At the source CU of the gNB, a handover request confirmation is received from the one or more candidate CUs. The handover request confirmation contains information about candidate distributed units (DUs) coupled to the one or more candidate CUs to form a list of candidate DUs. An index is assigned at the source CU of the gNB to the candidate DU coupled to the one or more candidate CUs; as well as Radio Resource Control (RRC) messages, which contain the list of candidate DUs coupled to the one or more candidate CUs and their assigned indices, are encoded at the source CU of the gNB and transmitted to the UE via the source DU of the gNB.

2. The apparatus of claim 1, wherein the one or more candidate CUs include CU spaces.

3. The apparatus of claim 1, wherein the one or more processors are further configured to: At the source CU of the gNB, the list of candidate DUs coupled to the one or more candidate CUs is sorted.

4. The apparatus of claim 1, wherein the one or more processors are further configured to: The list of candidate DUs coupled to the one or more candidate CUs and the assigned indexes are transferred from the source CU of the gNB to the source DU of the gNB.

5. The apparatus of claim 4, wherein the one or more processors are further configured to: Using the UE_CONTEXT_MODIFICATION procedure, the assigned index and the assigned index of the candidate DU coupled to the one or more candidate CUs are transferred from the source CU of the gNB to the source DU of the gNB.

6. The apparatus of claim 4, wherein the one or more processors are further configured to: The gNB receives confirmation from the source DU that the list of candidate DUs and the assigned indexes have been communicated to the UE.

7. The apparatus of claim 1, wherein the one or more processors are further configured to: The handover request is transmitted via the Xn interface between the source CU and the one or more candidate CUs, and the handover request confirmation is received.

8. The apparatus of claim 7, wherein the one or more processors are further configured to: The handover request confirmation is received at the source CU of the gNB from one or more candidate CUs, wherein at least one of the one or more candidate CUs is configured as follows: The UE CONTEXT_SETUP_REQUEST message transmits a request for Layer 1 / Layer 2 triggered mobility (LTM) information from each of the candidate DUs controlled by the at least one candidate CU; or The request for LTM information is transmitted to the selected DU controlled by the at least one candidate CU; as well as The HANDOVER_REQUEST_ACKNOWLEDGEMENT message transmits a list of candidate DUs containing the LTM information to the source CU.

9. The apparatus of claim 1, wherein the one or more processors are further configured to: The handover request is transmitted and the handover request confirmation is received via the NG interface between each CU and the network's Access and Mobility Management Function (AMF).

10. The apparatus of claim 9, wherein the one or more processors are further configured to: The handover request confirmation is received at the source CU of the gNB from one or more candidate CUs, wherein the AMF is configured as follows: In the NG CONTEXT MODIFICATION message, a request for mobility (LTM) information triggered by layer 1 / layer 2 is sent to each candidate CU.

11. The apparatus of claim 10, wherein the one or more processors are further configured to: The handover request confirmation is received at the source CU of the gNB from one or more candidate CUs, wherein at least one of the one or more candidate CUs is configured as follows: The UE context setup request / response (UE CONTEXT_SETUP_REQUEST / RESPONSE) message transmits a request for mobility (LTM) information triggered by Layer 1 / Layer 2 from each of the candidate DUs controlled by the at least one candidate CU. or The request for LTM information is transmitted to the selected DU controlled by the at least one candidate CU; as well as In the NG CONTEXT MODIFICATION ACKNOWLEDGEMENT message, a list of candidate DUs containing the LTM information is transmitted to the source CU.

12. The apparatus of claim 1, wherein the one or more processors are further configured to: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with inter-CU indication or intra-CU indication.

13. The apparatus of claim 1, wherein the one or more processors are further configured to: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with an indication of the next-hop parameter (NH) NH chain counter (NCC) between CUs.

14. The apparatus of claim 1, wherein the one or more processors are further configured to: At the source CU of the gNB, the list of candidate DUs coupled to one or more candidate CUs within the corresponding CU container is sorted. At the source CU of the gNB, the index is assigned to the candidate DU that is coupled to one or more candidate CUs within the corresponding CU container; and An index is assigned to the one or more candidate CUs at the source CU of the gNB.

15. The apparatus of claim 14, wherein the one or more processors are further configured to: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with inter-CU or intra-CU indications including CU indexes.

16. The apparatus of claim 1, wherein the one or more processors are further configured to: At the source CU of the gNB, the index is assigned to the candidate DU coupled to the one or more candidate CUs using information about the corresponding candidate CU.

17. The apparatus of claim 16, wherein all candidate DUs have a unique index.

18. The apparatus of claim 16, wherein the one or more processors are further configured to: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover between CUs having CU indices.

19. The apparatus of claim 18, wherein the CU index further comprises an LTM parent CU index (ltm-parentCU-r19).

20. A method for Layer 1 / Layer 2 triggered mobility (LTM) between central cells (CUs) at a next-generation node B (gNB), the method comprising: One or more candidate CUs for user equipment (UE) are determined at the source CU of the gNB; The handover request is transmitted from the source CU of the gNB to the one or more candidate CUs; At the source CU of the gNB, a handover request confirmation is received from the one or more candidate CUs. The handover request confirmation contains information about candidate distributed units (DUs) coupled to the one or more candidate CUs to form a list of candidate DUs. An index is assigned at the source CU of the gNB to the candidate DU coupled to the one or more candidate CUs; as well as Radio Resource Control (RRC) messages, which contain the list of candidate DUs coupled to the one or more candidate CUs and their assigned indices, are encoded at the source CU of the gNB and transmitted to the UE via the source DU of the gNB.

21. The method of claim 20, wherein the one or more candidate CUs include CUs.

22. The method according to claim 20, further comprising: The list of candidate DUs coupled to the one or more candidate CUs is sorted at the source CU of the gNB.

23. The method according to claim 20, further comprising: The list of candidate DUs coupled to the one or more candidate CUs and the assigned indexes are transferred from the source CU of the gNB to the source DU of the gNB.

24. The method according to claim 23, further comprising: Using the UE_CONTEXT_MODIFICATION procedure, the assigned index and the assigned index of the candidate DU coupled to the one or more candidate CUs are transferred from the source CU of the gNB to the source DU of the gNB.

25. The method according to claim 23, further comprising: The gNB receives confirmation from the source DU that the list of candidate DUs and the assigned indexes have been communicated to the UE.

26. The method according to claim 20, further comprising: The handover request is transmitted via the Xn interface between the source CU and the one or more candidate CUs, and the handover request confirmation is received.

27. The method according to claim 26, further comprising: The handover request confirmation is received at the source CU of the gNB from one or more candidate CUs, wherein at least one of the one or more candidate CUs is configured as follows: The UE CONTEXT_SETUP_REQUEST message transmits a request for Layer 1 / Layer 2 triggered mobility (LTM) information from each of the candidate DUs controlled by the at least one candidate CU; or The request for LTM information is transmitted to the selected DU controlled by the at least one candidate CU; as well as The HANDOVER_REQUEST_ACKNOWLEDGEMENT message transmits a list of candidate DUs containing the LTM information to the source CU.

28. The method according to claim 20, further comprising: The handover request is transmitted and the handover request confirmation is received via the NG interface between each CU and the network's Access and Mobility Management Function (AMF).

29. The method according to claim 28, further comprising: The handover request confirmation is received at the source CU of the gNB from one or more candidate CUs, wherein the AMF is configured as follows: In the NG CONTEXT MODIFICATION message, a request for mobility (LTM) information triggered by layer 1 / layer 2 is sent to each candidate CU.

30. The method according to claim 29, further comprising: The handover request confirmation is received at the source CU of the gNB from one or more candidate CUs, wherein at least one of the one or more candidate CUs is configured as follows: The UE context setup request / response (UE CONTEXT_SETUP_REQUEST / RESPONSE) message transmits a request for mobility (LTM) information triggered by Layer 1 / Layer 2 from each of the candidate DUs controlled by the at least one candidate CU. or The request for LTM information is transmitted to the selected DU controlled by the at least one candidate CU; as well as In the NG CONTEXT MODIFICATION ACKNOWLEDGEMENT message, a list of candidate DUs containing the LTM information is transmitted to the source CU.

31. The method according to claim 20, further comprising: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with inter-CU indication or intra-CU indication.

32. The method according to claim 20, further comprising: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with an indication of the next-hop parameter (NH) NH chain counter (NCC) between CUs.

33. The method according to claim 20, further comprising: At the source CU of the gNB, the list of candidate DUs coupled to one or more candidate CUs within the corresponding CU container is sorted. At the source CU of the gNB, the index is assigned to the candidate DU that is coupled to one or more candidate CUs within the corresponding CU container; and An index is assigned to the one or more candidate CUs at the source CU of the gNB.

34. The method according to claim 33, further comprising: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover with inter-CU or intra-CU indications including CU indexes.

35. The method according to claim 20, further comprising: At the source CU of the gNB, the index is assigned to the candidate DU coupled to the one or more candidate CUs using information about the corresponding candidate CU.

36. The method of claim 35, wherein all candidate DUs have a unique index.

37. The method of claim 35, further comprising: The Media Access Control-Control Element (MAC CE) is encoded at the source DU of the gNB, the MAC CE indicating a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover between CUs having CU indices.

38. The method of claim 37, wherein the CU index further comprises an LTM parent CU index (ltm-parentCU-r19).

39. An apparatus configured to cause a next-generation node B (gNB) to perform any of the methods described according to claims 20 to 38.

40. A next-generation node B (gNB) configured to perform any of the operations described herein.

41. A computer program product comprising computer instructions that, when executed by one or more processors, perform any of the operations described herein.

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