Configuration selection enhancements for layer 1 / layer 2 triggered mobility

Abstract

Generally, the current subject matter relates to configuration selection enhancements for mobility (LTM) for Layer 1 / Layer 2 (L1 / L2) triggers. In some implementations, configuration selection enhancement for LTM may include receiving, at a centralized unit control plane (CU-CP) of a base station, data from a first distributed unit (DU) of the base station, the data relating to an LTM handover (HO) configuration that is prepared for at least one service of a user equipment (UE), and may include, after receiving the data, transmitting the data to the first distributed unit (DU) of the base station. The second DU is requested by the CU-CP to prepare at least one LTM target cell configuration for the HO for at least one service of the UE in consideration of the data.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Indian Patent Application No. 202221060195 filed on October 21, 2022, entitled “Method and system for configuration selection enhancements for Lower Layer Mobility”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] In some implementations, the present subject matter relates to telecommunication systems, and in particular, to configuration selection enhancements for Layer 1 / Layer 2 (L1 / L2) Triggered Mobility (LTM). Background Art

[0004] In today's world, cellular networks provide on-demand communication capabilities for individuals and business entities. Typically, a cellular network is a wireless network that can be distributed over land areas (called cells). Each such cell is served by at least one fixed-position transceiver, which is called a cell site or base station. Each cell can use a different set of frequencies from its neighboring cells in order to avoid interference and provide better service within each cell. When the cells are linked together, they provide radio coverage over a wide geographic area, which enables a large number of mobile phones and / or other wireless devices or portable transceivers to communicate with each other and with fixed transceivers and phones anywhere in the network. Such communications are performed through base stations and can be completed even if the mobile transceiver passes through more than one cell during transmission. Major wireless communication providers have deployed such cell sites around the world, allowing communicating mobile phones and mobile computing devices to be connected to the public switched telephone network and the public Internet.

[0005] A mobile phone is a portable telephone that is capable of receiving and / or making telephone and / or data calls by transmitting signals to and from the mobile phone using radio waves through a cell site or a transmission tower. Given the large number of mobile phone users, current mobile phone networks provide limited and shared resources. In this regard, cell sites and mobile phones can change frequencies and use low-power transmitters to allow many callers to use the network simultaneously with less interference. The coverage range of a cell site can depend on a particular geographic location and / or the number of users who may potentially use the network. For example, in cities, a cell site may have a range of up to about 1 / 2 mile; in rural areas, this range may be up to 5 miles; and in some areas, users may receive signals from a cell site up to 25 miles away.

[0006] The following are some examples of digital cellular technologies used by communications providers: Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), cdmaOne, CDMA2000, Evolution-Data Optimized (EV-DO), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT), Data AMPS (IS-136 / TDMA), and Integrated Digital Enhanced Network (iDEN). Long Term Evolution or 4G LTE, developed by the 3rd Generation Partnership Project (3GPP) standards body, is a standard for high-speed data wireless communications for mobile phones and data terminals. 5G standards are currently being developed and deployed. 3GPP cellular technologies such as LTE and 5G NR are evolutions of earlier 3GPP technologies such as GSM / EDGE and UMTS / HSPA digital cellular technologies and allow for increased capacity and speed by using different radio interfaces and core network improvements.

[0007] A cellular network may be divided into a radio access network and a core network. A radio access network (RAN) may include network functions that may handle radio layer communication processing. A core network may include network functions that may handle high-level communications, such as Internet Protocol (IP), transport layer, and application layer. In some cases, the RAN functions may be split into baseband unit functions and radio unit functions, where, for example, a radio unit connected to a baseband unit via a fronthaul network may be responsible for low-level processing of a radio physical layer, while a baseband unit may be responsible for high-level radio protocols, such as MAC, RLC, etc.

[0008] A base station for a 5G cellular network may include a centralized unit (CU), one or more distributed units (DUs) communicatively coupled to the CU, and one or more radio units (RUs), each RU being communicatively coupled to at least one of the one or more DUs, and each RU being configured to be communicatively coupled to one or more mobile phones and / or other user equipment (UE). The CU may be logically split into a control plane part CU-CP, and one or more user plane parts (CU-UP). During the communication coupling process between the UE and the base station, the DU supporting the UE may change. In layer 1 / layer 2 (L1 / L2) triggered mobility (LTM) and multiple transmission reception points (mTRP), configuration preparation for switching from a serving cell to a target cell is always performed by the CU-CP, and the execution is performed by the DU. This means that the CU-CP needs to be able to decide what configuration to request from the DU at a given moment. In existing methods, there is a lack of knowledge of the configuration details at the CU, which makes it impossible for the CU-CP to select the required configuration from the target cell at the DU. Summary of the invention

[0009] In some implementations, the present subject matter relates to a computer-implemented method. The method may include: receiving, at a centralized unit control plane (CU-CP) of a base station, data from a first distributed unit (DU) of the base station, the data being related to preparing a layer 1 / layer 2 triggered mobility (LTM) handover (HO) configuration for at least one service of a user equipment (UE). The method may also include: after receiving the data, requesting, by the CU-CP, a second DU of the base station to prepare at least one LTM target cell configuration for the HO for at least one service of the UE taking into account the data.

[0010] This method may allow for enhanced configuration selection of the LTM at the DU, and allow the CU-CP to understand the situation of the DU and possible successful configurations at the DU.

[0011] In some implementations, the current subject matter can include one or more of the following optional features.

[0012] In some implementations, the data may include: timing advance information for each of the multiple cells of the DU. In addition, the CU-CP may receive the data during the process of establishing the F1 communication interface between the CU-CP and the first DU, and / or the CU-CP may receive the data in the F1 establishment request message sent from the first DU to the CU-CP; or, the timing advance information may include: average timing advance information for each of the multiple beams or beam groups of the multiple cells of the second DU for a given reference signal received power (RSRP) value, and before the CU-CP receives a message from the first DU that the UE needs a service change, the CU-CP may receive the average timing advance information from the first DU, and / or the CU-CP may periodically receive the data in a non-UE-related process between the CU-CP and the first DU.

[0013] In some implementations, the receiving may include: the CU-CP periodically receiving the data from the first DU before the CU-CP receives a message from the first DU that the UE requires a service change, and the method may also include: using machine learning at the CU-CP to formulate a HO strategy based at least in part on the received data. In addition, the data may include data about at least one of the following items: the type of UE, the speed of the UE, at least one service accessed by the UE at the first DU, and dynamic switching between the first cell and the second cell; and / or the method may also include: at the CU-CP, from the first DU that currently serves the UE for at least one service, receiving performance data about the first DU's service to the UE; and the request may request the second DU to prepare at least one LTM target cell while also taking into account the data received from the first DU.

[0014] In some implementations, the first DU may include at least one cell, the data may include resource availability of the at least one cell, and the receiving may include: before the CU-CP receives a message from the first DU that currently serves the UE for at least one service that a UE requires a service change, the CU-CP periodically receives resource availability from the first DU; and / or the resource availability may include availability at each of the at least one cell for the following items: inter-cell beam management (ICBM), LTM service cell change (SCC) with dynamic switching, multiple transmission reception points (mTRP), and LTM SCC.

[0015] In some implementations, the request may include sending an indication from the CU-CP to the second DU that the target cell configuration is at least one of ICBM, dynamic switching, and LTM SCC.

[0016] In some implementations, the CU-CP may receive the data from the first DU before the CU-CP receives a message from the first DU currently serving the UE for at least one service that the UE requires a service change.

[0017] In some implementations, the method may further include: selecting, at the CU-CP, a target cell configuration based at least in part on the received data.

[0018] In some implementations, a base station can have a disaggregated architecture.

[0019] In some implementations, the base station may include a next generation radio access network (NG-RAN) node, which includes a gNodeB or an ng-eNodeB.

[0020] In some implementations, a base station may include at least one processor and may include at least one non-transitory storage medium storing instructions that, when executed by the at least one processor, cause the at least one processor to perform the above method.

[0021] A non-transient computer program product (i.e., a physically embodied computer program product) storing instructions is also described, which, when executed by one or more data processors of one or more computing systems, causes at least one data processor to perform the operations described herein. Similarly, a computer system is also described, which may include one or more data processors and a memory coupled to the one or more data processors. The memory may temporarily or permanently store instructions that cause at least one processor to perform one or more of the operations described herein. In addition, the method may be implemented by one or more data processors within a single computing system or distributed between two or more computing systems. Such computing systems may be connected via one or more connections, and data and / or commands or other instructions may be exchanged, etc., including but not limited to direct connections between one or more computing systems in a plurality of computing systems, connections made through a network (e.g., the Internet, a wireless wide area network, a local area network, a wide area network, a wired network, etc.), etc.

[0022] The details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features and advantages of the subject matter described herein will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate certain aspects of the subject matter disclosed herein and, together with the description, help explain some of the principles associated with the disclosed implementations.

[0024] Figure 1a An exemplary conventional Long Term Evolution (LTE) communication system is illustrated;

[0025] Figure 1b Pictured Figure 1a Further details of the exemplary LTE system shown in;

[0026] Figure 1c Pictured Figure 1a Further details of the Evolved Packet Core of the exemplary LTE system shown in;

[0027] Figure 1d Pictured Figure 1a An exemplary evolved Node B of the exemplary LTE system shown in;

[0028] Figure 2 Pictured Figure 1a to Figure 1d Other details of the evolved Node B shown in;

[0029] Figure 3illustrates an exemplary virtual radio access network according to some implementations of the current subject matter;

[0030] Figure 4 illustrates an exemplary 3GPP split architecture for providing use of higher frequency bands to its users;

[0031] Figure 5a An exemplary 5G wireless communication system is illustrated;

[0032] Figure 5b An exemplary layer architecture of a split gNB and / or split ng-eNB (e.g., a next generation eNB that may be connected to a 5GC) is illustrated;

[0033] Figure 5c Pictured Figure 5a to Figure 5b An exemplary functional split in the gNB architecture shown in FIG.

[0034] Figure 6a illustrates an exemplary system according to some implementations of the current subject matter;

[0035] Figure 6b Illustration of some implementations of the current topic Figure 6a Exemplary alternative configurations of systems;

[0036] Figure 7a illustrates exemplary methods according to some implementations of the current subject matter;

[0037] Figure 7b Another exemplary method according to some implementations of the current subject matter is illustrated;

[0038] Figure 7c illustrates yet another exemplary method according to some implementations of the current subject matter;

[0039] Figure 7d illustrates yet another exemplary method according to some implementations of the current subject matter;

[0040] Figure 7e illustrates yet another exemplary method according to some implementations of the current subject matter;

[0041] Figure 8a illustrates an exemplary signaling diagram according to some implementations of the current subject matter;

[0042] Figure 8b illustrates another exemplary signaling diagram according to some implementations of the current subject matter;

[0043] Figure 8c illustrates yet another exemplary signaling diagram according to some implementations of the current subject matter;

[0044] Figure 8d illustrates yet another exemplary signaling diagram according to some implementations of the current subject matter;

[0045] Fig. 9 Illustration of some implementations of the current topic Figures 8a to 8d An exemplary architecture of a distributed unit (DU) in a signaling diagram of FIG.

[0046] Fig.10 illustrates an exemplary system according to some implementations of the current subject matter; and

[0047] Fig.11 Exemplary methods according to some implementations of the current subject matter are illustrated. DETAILED DESCRIPTION

[0048] The current subject matter can provide systems and methods that can be implemented in wireless communication systems. Such systems can include various wireless communication systems, including 5G new radio communication systems, long term evolution communication systems, etc.

[0049] Generally, the present subject matter relates to configuration selection enhancements for Layer 1 / Layer 2 (L1 / L2) Triggered Mobility (LTM).

[0050] Traditionally, to support L1 / L2-centric inter-cell changes (e.g., change of serving cell) in a decomposed gNB architecture, configuration occurs at the gNB-CU-CP, but the gNB-DU cannot perform the configuration autonomously without further interaction with upper layers. In LTM, as well as in multiple transmission reception points (mTRP), the configuration preparation for handover from a serving cell to a target cell is always performed by the CU-CP, and the execution is performed by the DU. This means that the CU-CP needs to be able to decide what configuration to request from the DU at a given moment. In existing approaches, the lack of knowledge of the configuration details at the CU prevents the CU-CP from selecting the required configuration from the target cell at the DU. As described herein, configuration selection enhancements for LTM can allow for configuration selection enhancements for LTM at the DU, and allow the CU-CP to understand the situation of the DU and the configurations that may be successful at the DU.

[0051] 3GPP standards and / or O-RAN Alliance standards may be relevant to one or more aspects of the current subject matter.

[0052] One or more aspects of the current subject matter may be incorporated into a transmitter and / or receiver component of a base station (e.g., gNodeB, eNodeB, etc.) in such a communication system. The following is a general discussion of long term evolution communication systems and 5G new radio communication systems.

[0053] Ⅰ. Long Term Evolution Communication System

[0054] Figure 1a to Figure 1c and Figure 2 An exemplary conventional Long Term Evolution (LTE) communication system 100 and its various components are illustrated. As is commercially known, the LTE system or 4G LTE is governed by a standard for high-speed data wireless communications for mobile phones and data terminals. The standard is an evolution of GSM / EDGE (Global System for Mobile Communications / Enhanced Data Rates for GSM Evolution) and UMTS / HSPA (Universal Mobile Telecommunications System / High Speed ​​Packet Access) network technologies. The standard is developed by 3GPP (Third Generation Partnership Project).

[0055] like Figure 1a As shown in FIG. 1 , the system 100 may include an evolved universal terrestrial radio access network (EUTRAN) 102, an evolved packet core (EPC) 108, and a packet data network (PDN) 101, wherein the EUTRAN 102 and the EPC 108 provide communication between a user equipment 104 and the PDN 101. The EUTRAN 102 may include a plurality of evolved Node Bs (eNodeBs or ENODEBs or eNodeBs or eNBs) or base stations 106 (a, b, c) (e.g., Figure 1b 100). The user equipment 104 may be a mobile phone, a smart phone, a tablet computer, a personal computer, a personal digital assistant (PDA), a server, a data terminal, and / or any other type of user equipment, and / or any combination thereof. The user equipment 104 may be connected to the EPC 108 via any eNodeB 106, and ultimately to the PDN 101. Typically, the user equipment 104 may be connected to the eNodeB 106 that is closest in distance. In the LTE system 100, the EUTRAN 102 and the EPC 108 work together to provide connectivity, mobility, and services for the user equipment 104.

[0056] Figure 1b Pictured Figure 1a 102. As described above, EUTRAN 102 includes multiple eNodeBs 106, also known as cell sites. eNodeBs 106 provide radio functions and perform key control functions, including scheduling of air link resources or radio resource management, active mode mobility or handover, and admission control of services. eNodeBs 106 are responsible for selecting which mobility management entities (MMEs, such as Figure 1c The eNodeBs 106 that make up the EUTRAN 102 cooperate with each other to perform radio resource management and handover.

[0057] Communication between the user equipment 104 and the eNodeB 106 is performed via an air interface 122 (also referred to as an LTE-Uu interface). Figure 1b As shown in FIG. 1 , the air interface 122 provides communication between the user equipment 104 b and the eNodeB 106 a. The air interface 122 uses orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC-FDMA), a variant of OFDMA, on the downlink and uplink, respectively. OFDMA allows the use of a variety of known antenna technologies, such as multiple input multiple output (MIMO).

[0058] The air interface 122 uses various protocols, including radio resource control (RRC) for signaling between the user equipment 104 and the eNodeB 106, and non-access stratum (NAS) for signaling between the user equipment 104 and the MME (eg, Figure 1c In addition to signaling, user traffic is transmitted between user equipment 104 and eNodeB 106. Both signaling and traffic in system 100 are carried by physical layer (PHY) channels.

[0059] Multiple eNodeBs 106 may be interconnected with each other using X2 interfaces 130 (a, b, c). Figure 1b As shown in FIG. 1 , X2 interface 130a provides interconnection between eNodeB 106a and eNodeB 106b; X2 interface 130b provides interconnection between eNodeB 106a and eNodeB 106c; X2 interface 130c provides interconnection between eNodeB 106b and eNodeB 106c. X2 interface can be established between two eNodeBs to provide exchange of signals, which may include load or interference related information, and handover related information. eNodeB 106 communicates with evolved packet core 108 via S1 interface 124 (a, b, c). S1 interface 124 can be split into two interfaces: one interface for control plane (such as Figure 1c The control plane interface (S1-MME interface) 128 in FIG. 128 ) and the other interface is used for the user plane (such as Figure 1c The user plane interface (S1-U interface) 125 is shown in FIG.

[0060] The EPC 108 establishes and enforces quality of service (QoS) for user services and allows the user device 104 to maintain a consistent Internet Protocol (IP) address when moving. It should be noted that each node in the network 100 has its own IP address. The EPC 108 is designed to interoperate with traditional wireless networks. The EPC 108 is also designed to separate the control plane (i.e., signaling) and the user plane (i.e., business) in the core network architecture, which allows greater flexibility in implementation and independent scalability of control and user data functions.

[0061] The EPC 108 architecture is dedicated to packet data and is Figure 1c 1. The EPC 108 includes a serving gateway (S-GW) 110, a PDN gateway (P-GW) 112, a mobility management entity (MME) 114, a home subscriber server (HSS) 116 (subscriber database of the EPC 108), and a policy control and charging rules function (PCRF) 118. Some of them (such as the S-GW, P-GW, MME, and HSS) are usually combined into nodes depending on the manufacturer's implementation.

[0062] The S-GW 110 acts as an IP packet data router and is the bearer path anchor for the user equipment in the EPC 108. Therefore, when the user equipment moves from one eNodeB 106 to another during mobility operation, the S-GW 110 remains unchanged and the bearer path toward the EUTRAN 102 is switched to talk to the new eNodeB 106 serving the user equipment 104. If the user equipment 104 moves to the domain of another S-GW 110, the MME 114 transfers all the bearer paths of the user equipment to the new S-GW. The S-GW 110 establishes a bearer path to one or more P-GWs 112 for the user equipment. If downlink data for an idle user equipment is received, the S-GW 110 buffers the downlink packets and requests the MME 114 to locate and reestablish the bearer path to and through the EUTRAN 102.

[0063] P-GW 112 is the interface between EPC 108 (and user equipment 104 and EUTRAN 102) and PDN 101 (such as Figure 1a112). P-GW 112 acts as a router for user traffic and performs functions on behalf of user equipment. These include IP address allocation for user equipment, packet filtering of downstream user traffic to ensure that it is placed on the appropriate bearer path, and implementation of downstream QoS (including data rate). Depending on the services the subscriber is using, there may be multiple user data bearer paths between user equipment 104 and P-GW 112. A subscriber may use services on PDNs served by different P-GWs, in which case the user equipment has at least one bearer path established to each P-GW 112. During handover of a user equipment from one eNodeB to another, if the S-GW 110 is also changing, the bearer path from the P-GW 112 is switched to the new S-GW.

[0064] The MME 114 manages the user equipment 104 within the EPC 108, including managing subscriber authentication, maintaining the context of the authenticated user equipment 104, establishing data bearer paths for user services in the network, and tracking the location of idle mobile devices that have not yet been detached from the network. For idle user equipment 104 that needs to be reconnected to the access network to receive downstream data, the MME 114 initiates paging to locate the user equipment and reestablishes the bearer path to and through the EUTRAN 102. The MME 114 for a specific user equipment 104 is selected by the eNodeB 106, and the user equipment 104 initiates system access from the MME 114. For the purpose of load sharing and redundancy, the MME is usually part of the MME set in the EPC 108. When the user's data bearer path is established, the MME 114 is responsible for selecting the P-GW 112 and the S-GW 110, which will constitute the end of the data path through the EPC 108.

[0065] PCRF 118 is responsible for policy control decisions and controls flow-based charging functions residing in the Policy Control Enforcement Function (PCEF) in P-GW 110. PCRF 118 provides QoS authorization (QoS Class Identifier (QCI) and bit rate) that determines how a particular data flow will be handled in the PCEF and ensures that this complies with the user's subscription profile.

[0066] As described above, IP services 119 are provided by PDN 101 (e.g. Figure 1a ).

[0067] Figure 1dThe diagram shows an exemplary structure of an eNodeB 106. The eNodeB 106 may include at least one remote radio head (RRH) 132 (typically there may be three RRHs 132) and a baseband unit (BBU) 134. The RRH 132 may be connected to an antenna 136. The RRH 132 and the BBU 134 may be connected using an optical interface that complies with the Common Public Radio Interface (CPRI) / Enhanced CPRI (eCPRI) 142 standard specification, which uses an RRH-specific custom control and user plane formulation method, or uses an O-RAN Alliance-compliant control and user plane formulation method. The operation of the eNodeB 106 can be characterized using the following standard parameters (and specifications): radio frequency band (Band 4, Band 9, Band 17, etc.), bandwidth (5, 10, 15, 20 MHz), access scheme (downlink: OFDMA; uplink: SC-OFDMA), antenna technology (single-user and multi-user MIMO; uplink: single-user and multi-user MIMO), number of sectors (up to 6), maximum transmission rate (downlink: 150 Mb / s; uplink: 50 Mb / s), S1 / X2 interface (1000Base-SX, 1000Base-T) and mobile environment (up to 350 km / h). The BBU 134 can be responsible for digital baseband signal processing, termination of S1 lines, termination of X2 lines, and call processing and monitoring control processing. From the EPC 108 ( Figure 1d IP packets received by the RRH 132 (not shown) may be modulated into digital baseband signals and transmitted to the RRH 132. Conversely, digital baseband signals received from the RRH 132 may be demodulated into IP packets for transmission to the EPC 108.

[0068] RRH 132 may use antenna 136 to transmit and receive wireless signals. RRH 132 may convert (using converter (CONV) 140) the digital baseband signal from BBU 134 into a radio frequency (RF) signal and power amplify (using amplifier (AMP) 138) it for transmission to user equipment 104 ( Figure 1d Conversely, RF signals received from user equipment 104 are amplified (using AMP 138 ) and converted (using CONV 140 ) to digital baseband signals for transmission to BBU 134 .

[0069] Figure 2Additional details of an exemplary eNodeB 106 are illustrated. The eNodeB 106 includes multiple layers: LTE Layer 1 202, LTE Layer 2 204, and LTE Layer 3 206. LTE Layer 1 includes a physical layer (PHY). LTE Layer 2 includes Media Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP). LTE Layer 3 includes various functions and protocols, including Radio Resource Control (RRC), dynamic resource allocation, eNodeB measurement configuration and provisioning, Radio Admission Control, Connection Mobility Control, and Radio Resource Management (RRM). The RLC protocol is an automatic repeat request (ARQ) segmentation protocol used on a cellular air interface. The RRC protocol handles the control plane signaling of LTE Layer 3 between user equipment and EUTRAN. RRC includes functions such as connection establishment and release, system information broadcast, radio bearer establishment / reconfiguration and release, RRC connection mobility procedures, paging notification and release, and outer loop power control. PDCP performs IP header compression and decompression, transmission of user data, and maintenance of sequence numbers for radio bearers. As Figure 1d As shown in FIG. 1 , BBU 134 may include LTE layers L1 to L3.

[0070] One of the main functions of the eNodeB 106 is radio resource management, which includes scheduling both uplink and downlink air interface resources for user equipment 104, controlling bearer resources and admission control. As an agent of the EPC 108, the eNodeB 106 is responsible for the transmission of paging messages used to locate mobile devices when the mobile device is idle. The eNodeB 106 also transmits common control channel information, header compression, encryption and decryption of user data sent over the air, and establishes switching reports and triggering criteria. As described above, the eNodeB 106 can collaborate with other eNodeBs 106 via the X2 interface to perform switching and interference management. The eNodeB 106 communicates with the MME of the EPC via the S1-MME interface and communicates with the S-GW via the S1-U interface. In addition, the eNodeB 106 exchanges user data with the S-GW via the S1-U interface. The eNodeB 106 and the EPC 108 have a many-to-many relationship to support load sharing and redundancy between the MME and the S-GW. The eNodeB 106 selects an MME from a group of MMEs so that multiple MMEs can share the load to avoid congestion. II. 5G NR wireless communication network

[0071] In some implementations, the current subject matter relates to a 5G New Radio (NR) communication system. 5G NR is the next telecommunication standard beyond the 4G / IMT Advanced standard. 5G networks offer higher capacity than current 4G, allowing more mobile broadband users per unit area, and allowing higher and / or unlimited gigabytes of data to be consumed per month and per user. This allows users to stream high-definition media for hours a day using mobile devices, even when Wi-Fi networks are not possible. 5G networks have improved support for inter-device communications, lower costs, lower latency than 4G devices, lower battery consumption, and so on. Compared to existing systems, such networks have data rates of tens of megabits per second for a large number of users, data rates of 100Mb / s for metropolitan areas, data rates of 1Gb / s for users in a limited area (e.g., an office building), a large number of simultaneous connections for wireless sensor networks, enhanced spectral efficiency, improved coverage, enhanced signaling efficiency, 1-10ms latency, and reduced latency.

[0072] Figure 3 An exemplary virtual radio access network 300 is illustrated. The network 300 can provide communications between various components, including base stations (e.g., eNodeBs, gNodeBs) 301, radio equipment 303, centralized units 302, digital units 304, and radio equipment 306. The components in the system 300 can be communicatively coupled to a core using backhaul links 305. The centralized unit (CU) 302 can be communicatively coupled to a distributed unit (DU) 304 using mid-haul connections 308. Radio frequency (RU) components 306 can be communicatively coupled to the DU 304 using fronthaul connections 310.

[0073] In some implementations, the CU 302 can provide smart communication capabilities to one or more DU units 304. The units 302, 304 can include one or more base stations, macro base stations, micro base stations, remote radio heads, etc., and / or any combination thereof.

[0074] In a low-layer split architecture environment, the CPRI bandwidth requirement for NR can be 100s of Gb / s. CPRI compression can be implemented in the DU and RU (e.g. Figure 3 In the 5G communication system, compressed CPRI on Ethernet frames is called eCPRI and is the recommended fronthaul network. This architecture can achieve standardization of fronthaul / midhaul, which can include high-layer split (e.g., option 2 or option 3-1 (upper / lower RLC split architecture)) and fronthaul with L1 split architecture (option 7).

[0075] In some implementations, the low-layer split architecture (e.g., Option 7) may include a receiver in the uplink, joint processing of multiple transmission points (TPs) for both DL / UL, and transmission bandwidth and latency requirements to facilitate deployment. In addition, the low-layer split architecture of the current subject matter may include a split between cell-level processing and user-level processing, which may include cell-level processing in a remote unit (RU) and user-level processing in a DU. In addition, using the low-layer split architecture of the current subject matter, frequency domain samples may be transmitted via Ethernet fronthaul, where the frequency domain samples may be compressed to reduce the fronthaul bandwidth.

[0076] Figure 4 An exemplary communication system 400 is illustrated that can implement 5G technology and can provide its users with the use of higher frequency bands (e.g., greater than 10 GHz). The system 400 can include a macro cell 402 and small cells 404, 406.

[0077] The mobile device 408 can be configured to communicate with one or more of the small cells 404 and 406. The system 400 can allow the control plane (C-plane) and the user plane (U-plane) to be split between the macro cell 402 and the small cells 404 and 406, where the C-plane and the U-plane use different frequency bands. In particular, the small cells 404 and 406 can be configured to utilize higher frequency bands when communicating with the mobile device 408. The macro cell 402 can utilize existing cellular frequency bands for C-plane communications. The mobile device 408 can be communicatively coupled via the U-plane 412, where the small cell (e.g., the small cell 406) can provide higher data rates and more flexible / cost-effective / energy-saving operations. The macro cell 402 can maintain good connectivity and mobility via the C-plane 410. In addition, in some cases, LTE and NR can be transmitted on the same frequency.

[0078] Figure 5a An exemplary 5G wireless communication system 500 according to some implementations of the current subject matter is illustrated. According to option 7-2, the system 500 can be configured to have a low-level split architecture. The system 500 may include a core network 502 (e.g., a 5G core), and one or more gNodeBs (or gNBs), wherein the gNB may have a centralized unit gNB-CU. The gNB-CU may be logically split into a control plane portion gNB-CU-CP 504, and one or more user plane portions gNB-CU-UP506. The control plane portion 504 and the user plane portion 506 may be configured to be communicatively coupled using an E1 communication interface 514 (as specified in the 3GPP standard). The control plane portion 504 may be configured to be responsible for executing the RRC protocol and the PDCP protocol of the radio stack.

[0079] According to the high-level split architecture, the control plane and user plane portions 504, 506 of the centralized unit of the gNB can be configured to be communicatively coupled to one or more distributed units (DU) 508, 510. The distributed units 508, 510 can be configured to execute the upper portions of the RLC, MAC, and PHY layer protocols of the radio stack. The control plane portion 504 can be configured to be communicatively coupled to the distributed units 508, 510 using the F1-C communication interface 516, and the user plane portion 506 can be configured to be communicatively coupled to the distributed units 508, 510 using the F1-U communication interface 518. The distributed units 508, 510 can be coupled to one or more remote radio units (RU) 512 via a fronthaul network 520 (which can include one or more switches, links, etc.), which in turn communicates with one or more user equipment (UE) devices. Figure 5a The remote radio unit 512 may be configured to execute the lower portion of the PHY layer protocol and provide antenna capabilities to the remote unit for communication with the user equipment (similar to the above in conjunction with Figure 1a to Figure 2 for discussion).

[0080] Figure 5b An exemplary layer architecture 530 for split gNB is illustrated. The architecture 530 may be Figure 5a The communication system 500 shown in FIG. 1 may be implemented as a virtualized decomposed radio access network (RAN) architecture, whereby layers L1, L2, L3 and radio processing may be virtualized and decomposed in (multiple) centralized units, (multiple) distributed units and (multiple) radio units. Figure 5b As shown in FIG. , the gNB-DU 508 may be communicatively coupled to the gNB-CU-CP control plane portion 504 (also shown in FIG. Figure 5a ) and a gNB-CU-UP user plane part 506. Each of components 504, 506, 508 may be configured to include one or more layers.

[0081] The gNB-DU 508 may include RLC, MAC, and PHY layers, as well as various communication sublayers. These may include the F1 Application Protocol (F1-AP) sublayer, the GPRS Tunneling Protocol (GTPU) sublayer, and the Stream Control Transmission Protocol (SCTP) sublayer, the User Datagram Protocol (UDP) sublayer, and the Internet Protocol (IP) sublayer. As described above, the distributed unit 508 may be communicatively coupled to the control plane portion 504 of the centralized unit, which may also include the F1-AP, SCTP, and IP sublayers, as well as the Radio Resource Control and PDCP Control (PDCP-C) sublayers. In addition, the distributed unit 508 may also be communicatively coupled to the user plane portion 506 of the centralized unit of the gNB. The user plane portion 506 may include the Service Data Adaptation Protocol (SDAP), PDCP User (PDCP-U), GTPU, UDP, and IP sublayers.

[0082] Figure 5c Pictured Figure 5a to Figure 5b Example functional split in the gNB architecture shown in Figure 1. Figure 5c As shown in FIG. 1 , the gNB-DU 508 may be communicatively coupled to the gNB-CU-CP 504 and the gNB-CU-UP 506 using an F1-C communication interface. The gNB-CU-CP 504 and the gNB-CU-UP 506 may be communicatively coupled using an E1 communication interface. The upper portion of the PHY layer (or Layer 1) may be performed by the gNB-DU 508, while the lower portion of the PHY layer may be performed by the RU ( Figure 5c Execute as shown in the figure. Figure 5c As shown in , the RRC and PDCP-C parts can be performed by the control plane part 504, and the SDAP and PDCP-U parts can be performed by the user plane part 506.

[0083] Some of the functions of the PHY layer in a 5G communication network may include error detection on a transport channel and indication to higher layers, FEC encoding / decoding of a transport channel, hybrid ARQ soft combining, rate matching of coded transport channels with physical channels, mapping of coded transport channels to physical channels, power weighting of physical channels, modulation and demodulation of physical channels, frequency and time synchronization, radio characteristic measurement and indication to higher layers, MIMO antenna processing, digital and analog beamforming, RF processing, and other functions.

[0084] The MAC sublayer of layer 2 may perform beam management, random access procedures, mapping between logical channels and transport channels, concatenating multiple MAC service data units (SDUs) belonging to one logical channel into a transport block (TB), multiplexing SDUs belonging to logical channels onto transport channels for delivery to / from the physical layer in / demultiplexing TBs delivered from the physical layer, scheduling information reporting, error correction through HARQ, priority handling between logical channels of one UE, priority handling between UEs with the aid of dynamic scheduling, transport format selection, and other functions. The functions of the RLC sublayer may include transmission of upper layer packet data units (PDUs), error correction through ARQ, reordering of data PDUs, duplication and protocol error detection, reconstruction, and the like. The PDCP sublayer may be responsible for transmission of user data, various functions during reconstruction, retransmission of SDUs, discard of SDUs in the uplink, transmission of control plane data, and the like.

[0085] The RRC sublayer of layer 3 may perform broadcasting of system information to NAS and AS, establishment, maintenance and release of RRC connections, security, establishment, configuration, maintenance and release of point-to-point radio bearers, mobility functions, reporting, and other functions.

[0086] III. Enhanced configuration selection of LTM

[0087] In general, a disaggregated architecture is defined in 3GPP that decomposes the gNodeB (gNB) into multiple logical entities. Similarly, a single DU can host multiple cells. Currently, a single DU can host up to 512 LTM target cells as per 3GPP standards. As mentioned above, the gNB-CU-CP hosts the PDCP and RRC layers, while the gNB-DU hosts the RLC, MAC, and PHY layers. Scheduling operations are performed at the gNB-DU.

[0088] Traditionally, to support L1 / L2-centric inter-cell changes (e.g., change of serving cell) in a decomposed gNB architecture, configuration occurs at the gNB-CU-CP, but the gNB-DU cannot perform the configuration autonomously without further interaction with upper layers. In LTM, as well as in multiple transmission reception points (mTRP), the configuration preparation for handover from a serving cell to a target cell is always performed by the CU-CP, and the execution is performed by the DU. This means that the CU-CP needs to be able to decide what configuration to request from the DU at a given moment. In existing approaches, the lack of knowledge of the configuration details at the CU prevents the CU-CP from selecting the required configuration from the target cell at the DU. As described herein, configuration selection enhancements for LTM can allow for configuration selection enhancements for LTM at the DU, and allow the CU-CP to understand the situation of the DU and the configurations that may be successful at the DU.

[0089] Layer 1 / Layer 2 Triggered Mobility (LTM) is an updated term for Low Layer Mobility (LLM). RAN2 has agreed on a definition of LTM. In general, LTM is a mobility procedure that allows the network to switch a UE from a source cell to a target cell without necessarily having to have a synchronized reconfiguration. In particular, based on the received L1 measurements, the network may indicate in L2 signaling (e.g. messages such as MAC CE) the beams belonging to the LTM candidate cells to which the UE should perform an LTM cell switching procedure. Prior to the execution of the LTM cell switching procedure, at least one LTM candidate cell configuration is provided by the network to the UE.

[0090] In some implementations of the current subject matter, a base station (e.g., Figure 5a gNodeB, Next Generation RAN (NG-RAN) node, such as eNodeB or gNodeB, etc.) can have a disaggregated architecture in which the base station includes a gNB-CU-CP (e.g., Figure 5a to Figure 5c gNB-CU-CP 504, etc.), and more than one CU-UP (e.g., Figure 5a to Figure 5c gNB-CU-UP 506, etc.) and gNB-DU (e.g., Figure 5a to Figure 5c gNB-DU 508, 510, etc.). The base station can be configured to provide configuration selection enhancements for LTM.

[0091] Figure 6a An exemplary system 600 configured to allow configuration selection enhancements for LTM is illustrated. In the illustrated implementation, base station 602 is configured in a manner similar to that described above. Figure 5a The 5G wireless communication system 500 is a gNB in ​​the 5G wireless communication system of FIG. 5 , but other base stations may also be configured similarly and used to provide configuration selection enhancements for LTM. Figure 6a In the illustrated implementation, the base station 602 includes multiple CU-UPs 606a, 606b, 606c. In the illustrated implementation, the base station 602 includes three CU-UPs 606a, 606b, 606c, but may also include other multiple CU-UPs. The CU of the base station 602 including multiple CU-UPs 606a, 606b, 606c is configured to communicate with the core network ( Figure 6a Not shown, for example Figure 5a 5GC 502, etc.) are communicatively coupled.

[0092] The CU of the base station 602 also includes a CU-CP 604 configured to be communicatively coupled to the user plane portions 606a, 606b, 606c of the CU using an E1 communication interface 614. In the illustrated implementation, the E1 interface 614 includes three communication links to reflect that the CU-CP 604 can be configured to communicate with three CU-UPs 606a, 606b, 606c.

[0093] The base station 602 also includes a plurality of DUs 608, 610. In the illustrated implementation, the base station 602 includes two DUs 608, 610, but may include other plurality of DUs. The CU-CP 604 is configured to be communicatively coupled to the DUs 608, 610 using an F1-C communication interface 616. The CU-UPs 606a, 606b, 606c are configured to be communicatively coupled to the DUs 608, 610 using an F1-U communication interface 618. In the illustrated implementation, the F1-U interface 618 associated with each of the DUs 608, 610 includes three communication links to reflect that each DU 608 and 610 may be configured to communicate with three CU-UPs 606a, 606b, 606c.

[0094] The base station 602 also includes a plurality of RUs 612. In the illustrated implementation, the base station 602 includes five RUs 612, but may include other plurality of RUs. The RUs 612 are configured to be communicatively coupled to the DUs 608, 610 via a fronthaul network 620. In addition, each of the RUs 612 is configured to be communicatively coupled to one or more UEs 622. In the illustrated implementation, two of the RUs 612 are shown to be communicatively coupled to one UE 622, two of the RUs 612 are shown to be communicatively coupled to two UEs 622, and one of the RUs 612 is shown to be communicatively coupled to three UEs 622, but each of the RUs 612 may be coupled to other numbers of UEs that are the same or different than any other RU 612.

[0095] Secure L1 / L2-centric inter-cell mobility execution may be configured to occur when one of the UEs communicatively coupled to the base station 602 is handed over from one of the DUs 608, 610 of the base station 602 to another of the DUs 608, 610 also belonging to the same base station 602. One of the DUs 608, 610 currently serving the UE 622 is referred to as a "serving DU" because it is currently serving the UE 622, e.g., currently serving the UE 622. One of the DUs 608, 610 to which the UE's service is being handed over is referred to as a "target DU" because its target is to provide service to the UE 622.

[0096] refer to Figure 6b A system is also described in which secure L1 / L2-centric inter-cell mobility can be configured. Figure 6b Pictured Figure 6a CU-CP 604 and CU-UP 606a, 606b, 606b, but in Figure 6b In the illustrated implementation, the base station 602 includes more than two DUs. Figure 6b In the illustrated implementation, the base station 602 includes 66 DUs. Three of the DUs 628a, 628b, and 628c are macro cells (in Figure 6b 1, Macro 2, and Macro 3), and 63 of the DUs 626 are small cells (nine of which are in Figure 6b The base station 602 may include other numbers of macro cells and / or other numbers of small cells. The macro 1 DU 628a, macro 2 DU 628b, and 21 small cell DUs 626 including gNB-DU10, gNB-DU20, and gNB-DU30 are configured to be provided by the first CU-UP 606a (in FIG. Figure 6b The macro 1 DU 628a, macro 2 DU 628b, macro 3 DU 628c, and 21 small cell DUs 626 including gNB-DU40, gNB-DU50, and gNB-DU60 are configured to be served by the second CU-UP 606b ( Figure 6b The macro 2 DU 628b, macro 3 DU 628c, and 21 small cell DUs 626 including gNB-DU 70, gNB-DU 80, and gNB-DU 90 are configured to be served by the third CU-UP 606c (in Figure 6b 3) services marked as CU-UP.

[0097] exist Figure 6b In the illustrated implementation, each CU-UP 606a, 606b, 606c serves a subset of DUs 626, 628a, 628, 628c for all services. However, a CU-UP may serve all DUs of a base station for one service (e.g., enhanced mobile broadband (eMBB)) while serving a subset of DUs for another service (e.g., vehicle-to-everything (V2X) or ultra-reliable low latency communications (URLLC)).

[0098] Figure 7aAn exemplary method 700 according to some implementations of the current subject matter is illustrated. Figure 7a Method 700 is about Figures 8a to 8d , but may similarly be implemented with other systems, such as Figure 1a to Figure 1c and Figure 2 System 100, Figure 4 System 400, Figure 5a System 500, Figure 6a and Figure 6b systems, etc. Figures 8a to 8d The system 800 is a 5G system, but as described above, the configuration selection enhancements for LTM described herein can be performed using other types of wireless communication systems, such as an LTE wireless communication system, or a 6G or higher generation wireless communication system. Figures 8a to 8d The various elements in the system 800 are numbered as sequential steps, but such numbering does not indicate that these numbered steps can only be performed in this order in the system 800. Figures 8a to 8d There may be one or more additional steps before and / or after any one or more of the sequentially numbered steps shown in .

[0099] In system 800, a UE (e.g., Figure 1a to Figure 1c UE 104, Figure 6a UE 622, etc.) ( Figures 8a to 8d ) is configured with an LTM, which is configured at a base station (e.g., a gNB (e.g., Figure 5a gNodeB, Figure 6a and Figure 6b One or more DUs 802, 804 (e.g., Figure 5a to Figure 5c DU 508 Figure 5a DU 510 Figure 6a DU 608 Figure 6a DU 610 Figure 6b DU 626 Figure 6b DUs 628a, 628b, 628c, etc.) of the system 800 may have one or more target cells. More than one UE may be communicatively coupled to the base station, and / or the base station may include more than two DUs. The base station of the system 800 also includes a CU, which includes a CU-CP 806 (e.g., Figure 5a to Figure 5c gNB-CU-CP 504, Figure 6a and Figure 6b CU-CP 604, etc.), and one or more CU-UPs (e.g., Figures 5a to 5c gNB-CU-UP 506, Figure 6a and Figure 6bCU-UP 606a, 606b, 606c, etc.) ( Figures 8a to 8d ), and multiple RUs (e.g., Figure 5a RU 512, Figure 6a RU 612, etc.) ( Figure 8a-8d 802). The UE is currently served by the first DU 802 of the base station. Figures 8a to 8d Base stations and core networks (for example, Figure 1a to Figure 1c and Figure 2 EPC 108 Figure 5a 5GC 502, etc.) ( Figures 8a to 8d ) are communicatively coupled.

[0100] like Figure 7a As shown in Figures 8a to 8d The F1 communication interface is established between the second DU (in the figure) and the CU-CP 806. Figures 8a to 8d An F1 communication interface is established 704 between gNB-DU2) 802 and CU-CP 806. The F1 communication interface may be established 702, 704 according to the 3GPP standard. Figure 7a It is shown that a 702F1 communication interface is established between the first DU 802 and the CU-CP 806 before an F1 communication interface is established between the second DU 804 and the CU-CP 806, but a 704F1 communication interface may also be established between the second DU 806 and the CU-CP 806 before the 702F1 communication interface is established between the first DU 802 and the CU-CP 806.

[0101] During use of the first DU 802, the first DU 802 may provide at least one service to the UE. The method 700 illustrates an implementation of an inter-DU LTM serving cell change scenario, which includes a first DU (also referred to herein as a serving DU) 802 determining 706 that the UE requires a serving cell change. The serving DU determination 706 may include the serving DU 802 analyzing, according to 3GPP standards, an intra-frequency L1 measurement report sent by the UE to the serving DU 802. According to 3GPP standards, the intra-frequency L1 measurement report may include layer 1 (L1) measurements that may be analyzed by the first DU 802 when making resource control decisions, which may include a serving cell change, where for at least one service, the UE will be served by a DU (e.g., the second DU 804) (rather than the first DU 802).

[0102] In response to determining 706 that a serving cell change should occur, the serving DU 802 notifies 708 the UE of the serving cell change. The notification to the UE may include the serving DU 802 sending a serving cell change command, such as a MAC CE, to the UE.

[0103] Likewise, in response to determining that a cell service change should occur, the serving DU 804 notifies 708 the CU-CP 806 that a serving cell change of the UE has occurred. Thus, the notification 708 may identify the UE to the CU-CP 806 using an identifier known to the serving DU 802, such as in accordance with the 3GPP standard, which uniquely identifies the UE to the CU-CP 806. The notification 708 to the CU-CP 806 may include the serving DU 802 using the F1 communication interface previously established 702 to send a serving cell change notification message to the CU-CP 806. The serving cell change notification message may include a cell identification (ID) that uniquely identifies the UE that has undergone a serving cell change.

[0104] In response to receiving the serving cell change command from the serving DU 802, the UE may send a radio resource control (RRC) reconfiguration confirmation message to the CU-CP 806. The CU-CP 806 learns from the RRC reconfiguration confirmation message that the completion of the successful serving cell change is confirmed to the UE uniquely identified by the serving DU 802 to the CU-CP 806.

[0105] Likewise, in response to receiving the layer 3 RRC measurement configuration, the UE may send 822 an RRC measurement report, in accordance with 3GPP standards, to the CU-CP 806. In accordance with 3GPP standards, the RRC measurement report may include layer 3 (L3) measurements, which may be analyzed by the CU-CP 806 when making resource control decisions, which may include deciding to prepare at least one target cell for LTM such that, for at least one service, at least one target cell from the target DU 804 is ready to serve the UE (rather than the DU 804).

[0106] In response to deciding to prepare the at least one target cell for LTM, the CU-CP 806 selects 710 a configuration for the at least one target cell for LTM. As discussed further below, the configuration may be selected 710 using data previously received by the CU-CP 806.

[0107] like Figures 8a to 8dAs shown in the end, in these illustrated implementations, each of the at least one target cell is an inter-DU target cell, e.g., is part of a different DU than the serving DU 802, where the same CU (e.g., a CU including the CU-CP 806) serves each DU 802, 804. Also, in these illustrated implementations, since there are only two gNB-DUs, the at least one target cell only includes the target DU 804, but as described above, the base station may include more than two target cells. Currently, according to the 3GPP standard, up to eight LTM target cells can be prepared for a given UE.

[0108] Preparing at least one target cell for LTM may include CU-CP 806 notifying at least one target DU 804 that the at least one target DU 804 may be notified later to start providing services to the UE for at least one service. Thus, the target DU 804 may reserve necessary resources for the UE. Figure 7a As shown in , notifying at least one target cell (in the illustrated implementation, only the target DU 804) may include the CU-CP 806 requesting the target DU 804 to prepare at least one target cell according to the prepared configuration. The request may include the CU-CP 806 sending a UE context establishment request message to the target DU 804 using the F1 communication interface previously established 704 according to the 3GPP standard.

[0109] In some implementations, the CU-CP 806 may select a configuration for at least one target cell for the LTM using data received from at least one DU 802, 804 during an F1 setup process in which an F1 communication interface is established between the DU and the CU-CP 806. A handover (HO) from one cell of a DU of a base station to another cell of another DU of a base station occurs only after the F1 communication interface is established with each DU. Thus, the CU-CP 806 receiving the HO-related data during the F1 setup process may ensure that the CU-CP 806 has the HO-related data on hand before the HO is needed.

[0110] In some implementations, such as Figure 7b and Figure 8a As illustrated in , the HO-related data received by the CU-CP 806 during F1 establishment includes timing advance information for one or more cells of the DU. Timing advance (TA) refers to the time offset between the start of the received downlink subframe and the start of the transmitted uplink subframe at the UE. This offset at the UE is necessary to ensure downlink and uplink subframe synchronization at the base station serving the US. This is a MAC layer (layer 2) control element (CE) from the base station to the UE, which is used to control the uplink (e.g., UE to base station) signal transmission timing.

[0111] The CU-CP 806's knowledge of TA information for one or more cells of the first DU and for one or more cells of the second DU may allow the CU-CP 806 to determine whether each of at least one target cell (e.g., one or more cells of the second DU 804) is a candidate for a random access channel layer-less (RACH-less) HO from the serving DU 802 based on whether the TA of the target cell is zero or the TA of the serving cell is the same as the TA of the target cell. If the TA of the target cell is zero or the TA of the serving cell is the same as the TA of the target cell, the target cell is a candidate for RACH-less HO. Therefore, the CU-CP 806 may request 712 that at least one target cell of the second DU 804 be prepared for RACH-less HO if possible, otherwise be prepared for RACH-based HO. Therefore, HO from one cell of the serving DU 802 to another cell of the target DU 804 may consume less time, because HO from the serving cell to one of the at least one target cell has been prepared at each of the one or more target cells to include a contention-free RACH procedure (for RACH-free HO) or a contention-based RACH procedure (for RACH-based HO). Therefore, handover delay may be reduced, and thus user plane interruption time may be reduced.

[0112] As described above, a communication interface 702, 704F1 is established between the CU-CP 806 and each of the first DU 802 and the second DU 804. Figure 7b and Figure 8a As shown in FIG. 702 , establishing 722 an F1 communication interface between the first DU 802 and the CU-CP 806 includes the service DU 802 sending 808 an F1: setup request to the CU-CP 806, the F1: setup request including TA information for all beams / beam groups for each cell of the service DU 802. The service DU 802 sends 808 an F1: setup request to the CU-CP 806. Figure 8a 806 is shown as having multiple cells, including cell 1, cell 2, etc., but the serving DU 802 may include a single cell or two or more cells. In response to receiving the F1: setup request from the serving DU 802, the CU-CP 806 sends 810 an F1: setup response to the serving DU 802.

[0113] like Figure 7b and Figure 8aAs shown in FIG. 8 , during the F1 establishment process (where the F1 communication interface is established 704, 724 between the CU-CP 806 and the target DU 804), the target DU 804 sends 812 an F1: establishment request to the CU-CP 806, which includes TA information of all beams / beam groups of each cell of the target DU 804. Figure 8a 804, but the target DU 804 may include a single cell, or may include two or more cells. In response to receiving the F1: setup request from the target DU 804, the CU-CP 806 sends 814 an F1: setup response to the target DU 804.

[0114] Figure 7a , Figure 7b and Figure 8a It is shown that the 702, 722F1 communication interface is established between the service DU 802 and the CU-CP 806 before the 704, 724F1 communication interface is established between the target DU 804 and the CU-CP 806, but the 704, 724F1 communication interface can be established between the target DU 804 and the CU-CP 806 before the 702, 722F1 communication interface is established between the service DU 802 and the CU-CP 806.

[0115] In some implementations, such as Figure 8a As shown in , CU-CP 806 can provide TA information received from one DU to each of the other DUs of the base station. Therefore, each DU can know the TA of the cell of the other DU and thus know whether RACH-free HO to the cell of the other DU can be performed. Figure 8a As shown in the figure, the CU-CP 806 can send 816 TA information of one or more cells of the second DU (also referred to as neighboring DU in this document) 804 to the first DU 802, for example in a gNB-CU configuration update message, and can send 818 TA information of one or more cells of the first DU 802 to the second DU 804, for example in a gNB-CU configuration update message. Figure 8a The CU-CP is shown sending 816TA information to the first DU 802 before sending 818TA information to the second DU 804 , but may send 818TA information to the second DU 804 before sending 816TA information to the first DU 802 .

[0116] In some implementations, after establishing 702, 704F1 communication interfaces between the CU-CP 806 and each of the first DU 802 and the second DU 804, the CU-CP 806 may select a configuration for at least one target cell of the LTM using data received from at least one DU 802, 804. The data may also be received before the CU-CP 806 receives a notification 708 from the serving DU 802 that the UE requires a service change. A handover (HO) from one cell of a DU of a base station to another cell of another DU of a base station only occurs when the CU-CP 806 receives a notification that such a change is required. Therefore, the CU-CP 806 receiving data related to the HO before receiving the notification 708 from the serving DU 802 can ensure that the CU-CP 806 has data related to the HO on hand before the HO is required.

[0117] In some implementations, such as Figure 7c and Figure 8b As illustrated in FIG, where the CU-CP 806 receives data related to HO after F1 is established and before the CU-CP 806 receives a notification 708 that the UE needs to change the serving cell, the CU-CP 806 can use data collection and training algorithms based on machine learning (ML) to determine the possibility of dynamic conversion. As will be appreciated by those skilled in the art, machine learning may involve artificial intelligence (AI). Before the CU-CP 806 receives a notification 708 that the UE needs to change the serving cell, the CU-CP 806 may periodically receive data related to HO, and the CU-CP may use machine learning to formulate a HO strategy based at least in part on the received data. The CU-CP 806 may also provide a strategy to the DUs 802 and 804 of the base station so that before at least one target cell needs to be prepared for LTM, the DUs 802 and 804 know the strategy indicating how to prepare at least one target cell for LTM.

[0118] The data that the CU-CP 806 may collect from the DUs 802, 804 and use in the formulation may include data regarding at least one of the type of UE, the speed of the UE, at least one service accessed by the UE at the serving DU 802, and dynamic switching between a first cell of the serving DU 802 and a second cell of the serving DU 802.

[0119] UE type (and / or capability), speed, and accessed services can enable machine learning at CU-CP 806 to identify the type of UE undergoing dynamic conversion, and generate different policies for different types of UE. Different policies are used for different UEs, which indicates that different UEs can have different types of mobility. For example, a cellular phone (a first type of UE) is generally more mobile than a laptop (a second type of UE), and a laptop is generally more mobile than a parking meter (a third type of UE). For another example, a smart watch (a fourth type of UE) is generally more mobile than a game console (a fifth type of UE), and a game console is generally more mobile than a server (a sixth type of UE). Examples of UEs include cellular phones, smart phones, session initiation protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems (GPS), multimedia devices, video devices, digital audio players (e.g., MP3 players, etc.), cameras, game consoles, tablets, smart devices, wearable devices (e.g., smart watches or other devices), vehicles, electric meters, gas pumps, large and small kitchen appliances, healthcare equipment, implants, sensors / actuators, displays, or any other similarly functional device. A UE may be an Internet of Things (IoT) device (e.g., a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, etc.).

[0120] Dynamic switching is a phenomenon in which the network expects to ping-pong between the serving cell and the target cell, and prepares the serving cell and the target cell to be equipped for this back-and-forth switching. Associating dynamic switching with UE type can be used to optimize network planning in loaded cells. Data about the dynamic switching between the first cell of the serving DU 802 and the second cell of the serving DU 802 may include the identification of the first cell and the second cell, the frequency of switching including source and target beam information, the time of day when the dynamic switching occurs, and / or the key resources at the serving DU 802 that are overloaded due to the dynamic switching. Associating source and target beam information with UE type can be used to optimize network planning in loaded cells. Knowing the time of day can achieve optimized resource planning in cells undergoing dynamic switching. Knowing the overload of key resources can help CU-CP 806 optimize resource management.

[0121] like Figure 7c and Figure 8bAs shown in , the first DU 802 may periodically send 730, 820 HO-related data to the CU-CP 806, the data including at least one of the type of UE, the speed of the UE, at least one service accessed by the UE at the serving DU 802, and a dynamic switch between a first cell of the serving DU 802 and a second cell of the serving DU 802. The second DU 804 may also periodically send 732, 822 HO-related data to the CU-CP 806, the data including at least one of the type of UE, the speed of the UE, at least one service accessed by the UE at the second DU 804, and a dynamic switch between a first cell of the second DU 804 and a second cell of the second DU 804. Figure 7c and Figure 8b As shown in , the data may be sent 730 , 820 in a status report message from the serving DU 802 via the F1 interface previously established 702 , and may be sent 732 , 822 in a status report message from the target DU 804 via the F1 interface previously established 704 . Figure 8b It is shown that the first DU 802 sends 730, 820 data to the CU-CP 806 before the second DU 804 sends 732, 832 data to the CU-CP 806, but it may also be that the second DU 804 sends 732, 832 data to the CU-CP 806 before the first DU 802 sends 730, 820 data to the CU-CP 806.

[0122] The timing of periodic reports from DU 802, 804 may be pre-programmed and may be based on one or more factors. For an example of a factor, the periodic report may be sent according to a predetermined schedule so that the report is regularly received by CU-CP 806. For another example of a factor, the periodic report may be sent after a predetermined number of serving cell changes occur within the DU (e.g., a predetermined number of dynamic conversions occur). For yet another example of a factor, the periodic report may be sent based on the size of the report. The report may be large because a DU typically serves multiple UEs and data will be sent to CU-CP 806 for each UE.

[0123] The CU-CP 806 generates and formulates 824 a handover policy using an ML-based data collection and training algorithm based at least in part on the data received from the DUs 802, 804 in the status reports. The CU-CP 806 may be configured to repeatedly generate and formulate 824 the policy as new data is received. The ML-based data collection and training algorithm is RRM-specific and, therefore, vendor-specific. In other words, a vendor of the CU-CP 806 (e.g., a vendor of a gNB that includes the CU-CP 806) may build its own algorithm to manage resources and configure the UE according to the needs of that particular vendor.

[0124] The CU-CP 806 notifies 736 the first DU 802 and the second DU 804 of the switching strategy including its parameters and values. Figure 8b As shown in , the notification 736 may include the CU-CP 806 sending 826 a gNB-CU configuration policy message to the first DU 802 via the F1 communication interface previously established 702, and sending 828 a gNB-CU configuration policy message to the second DU 804 via the F1 communication interface previously established 704. Figure 8b The CU-CP 806 is shown sending 826 the switching policy to the first DU 802 before sending 828 the switching policy to the second DU 804 , but the CU-CP 806 may send 826 the switching policy to the first DU 802 after sending 828 the switching policy to the second DU 804 .

[0125] like Figure 8b As shown in , after notifying 736 the switching strategy to the first DU 802 and the second DU 804, the CU-CP 806 can use the performance feedback sent 830 from the first DU 802 to the CU-CP 806, and the performance feedback sent 832 from the second DU 804 to the CU-CP 806 to fine-tune 834 the ML-based data collection and training algorithm. As a result, the algorithm can become more effective over time. The performance feedback can be sent 830, 832 any number of times, and thus the fine-tuning 834 can be repeated any number of times.

[0126] In some implementations, such as Figure 7d and Figure 8cAs shown in , where the CU-CP 806 receives HO-related data after F1 is established and before the CU-CP 806 receives the notification 708 that the UE needs to change the serving cell, the HO-related data received by the CU-CP 806 includes resource availability of one or more cells of the DU. The resource availability includes availability for one or more of ICBM, dynamic switching, mTRP, and LTM SCC at each of the one or more cells. In some implementations, the availability of each of ICBM, dynamic switching, mTRP, and LTM SCC is provided to the CU-CP 806, which can allow the CU-CP 806 to understand as much as possible the available resources at the cell / beam group and make an informed configuration decision for the target cell.

[0127] like Figure 7d and Figure 8c As shown in , the first DU 802 may periodically send 738, 836 HO-related data, which includes resource availability of one or more cells of the first DU. The second DU 804 may also periodically send 740, 838 HO-related data to the CU-CP 806, which includes resource availability of one or more cells of the second DU. Figure 8c It is shown that the first DU 802 sends 738, 836 data to the CU-CP 806 before the second DU 804 sends 740, 838 data to the CU-CP 806, but it may also be that the second DU 804 sends 740, 838 data to the CU-CP 806 before the first DU 802 sends 738, 836 data to the CU-CP 806. The periodic reporting of resource availability reflects that resources may become available or unavailable based on one or more new UEs being served by a particular DU, a particular DU stopping serving one or more UEs, and / or a change in demand for one or more UEs being served by a particular DU.

[0128] The timing of periodic reports from DU 802, 804 may be pre-programmed and may be based on one or more factors. For an example of a factor, the periodic report may be sent according to a predetermined schedule so that the CU-CP 806 can receive the report regularly. For another example of a factor, the periodic report may be sent after a predetermined number of serving cell changes occur within the DU (e.g., a predetermined number of dynamic conversions occur). For another example of a factor, the periodic report may be sent based on the size of the report. The report may be large because the DU typically serves multiple UEs and data about each UE will be sent to the CU-CP 806.

[0129] In some implementations, such as Figure 7e and Figure 8dAs illustrated in , after F1 is established and before CU-CP 806 receives notification 708 that the UE needs to change the serving cell, CU-CP 806 receives data related to HO, and the data related to HO received by CU-CP 806 includes timing advance information for one or more beams or beam groups of the DU. The timing advance information can be an average timing advance value used by the UE in each beam or beam group for a given reference signal received power (RSRP) value or RSRP range. Therefore, the data provided to CU-CP 806 may also include an RSRP value or range, and a beam or beam group associated with a given average TA value. CU-CP 806 can use the received average TA information to determine the feasibility of ICBM at the target DU cell. The DU providing the average TA value can be configured to calculate the average TA so that such information can be provided to CU-CP 806.

[0130] like Figure 7e and Figure 8d As shown in , the CU-CP 806 may send 742, 850 a request for HO-related data to the first DU 802, the data including the average TA, RSRP, and beam or beam group. In response to receiving the request from the CU-CP 806, the first DU 802 sends 852 a response to the CU-CP 806 confirming the request, and sends 854 the requested HO-related data to the CU-CP 806, the data including the average TA, RSRP, and beam or beam group. Figure 8d As shown in , the request may be an F1 resource status request message, the response confirmation may be an F1 resource status response message, and the requested data may be sent 854 in an F1 resource status update message. The CU-CP 806 may also send 744, 856 a request for HO-related data to the second DU 804, the data including the average TA, RSRP, and beam or beam group. In response to receiving the request from the CU-CP 806, the second DU 804 sends 858 a response to the CU-CP 806 confirming the request, and sends 860 the requested HO-related data to the CU-CP 806, the data including the average TA, RSRP, and beam or beam group. Figure 8d As shown in , the request may be an F1 Resource Status Request message, the response confirmation may be an F1 Resource Status Response message, and the requested data may be sent in an F1 Resource Status Update message 860. Figure 8d CU-CP 806 is shown to request data from first DU 802 before second DU 804, but CU-CP 806 may request data from second DU 804 before first DU 802. In addition, Figure 8dThe first DU 802 and the second DU 804 are illustrated as sending the average TA, RSRP, and beam or beam group to the CU-CP 806 in a resource status update message via the F1 communication interface previously established 702, 704, respectively. However, the first DU 802 and the second DU 804 may send the average TA, RSRP, and beam or beam group to the CU-CP 806 in another non-UE related message, such as in a gNB-DU configuration update message, respectively. In addition, the RSRP values ​​sent 742, 744, 854, 860 may be categorized into a small range to reduce implementation complexity.

[0131] The average TA, RSRP, and beam or beam group may be periodically sent 742, 744, 854, 860 from the DU to the CU-CP 806. Alternatively, the CU-CP 806 may request 850 the average TA, RSRP, and beam or beam group information from the serving DU 802 whenever an inter-DU LTM target cell is prepared.

[0132] In some implementations, such as Figure 8d As shown in , CU-CP 806 can provide RSRP, beam or beam group, and average TA information received from one DU to each other DU of the base station. Therefore, each DU can know the average TA of the beam / beam group of other DUs, and thus know whether ICBM is feasible, for example, whether ICBM can be configured for UEs in a given target cell. The UE providing RSRP for a target cell with a given timing advance value at the serving cell can be compared with the information received from the target DU 804 to determine whether ICBM is feasible in the target DU cell. Figure 8d As shown in, the CU-CP 806 may send 862RSRP, a beam or a beam group, and an average TA information of one or more beams or beam groups of the second DU 804 to the first DU 802, for example in an F1 gNB-CU configuration update message, and may send 864RSRP, a beam or a beam group, and an average TA information of one or more beams of the first DU 802 to the second DU 804, for example in an F1 gNB-CU configuration update message. Figure 8d The CU-CP is shown sending 862 the average TA information to the first DU 802 before sending 864 the average TA information to the second DU 804 , but the average TA information may be sent 864 to the second DU 804 before the average TA information is sent 862 to the first DU 802 .

[0133] Reference again Figure 7aIn response to receiving a request from the CU-CP 808, for example, in response to receiving a UE context setup request message from the CU-CP 808, the target DU 804 prepares 712 each target cell in the at least one target cell for LTM. In the illustrated implementation, the at least one target cell includes only the target DU 804 that prepares one target cell.

[0134] The target DU 804 notifies the CU-CP 806 that the preparation has been completed. The notification to the CU-CP 806 may include the target DU 804 sending a UE context setup response message to the CU-CP 806 using the previously established 704 F1 communication interface according to the 3GPP standard.

[0135] In some implementations, the CU-CP 806 requesting the target DU 804 to prepare at least one target cell may include: the CU-CP 806 sending an indication that the target cell configuration is at least one of ICBM, dynamic switching, and LTM SCC. The CU-CP 806 previously received at least one resource availability report from the second DU 804 (e.g., as described above with respect to Figure 7d and Figure 8c The foregoing) may allow the CU-CP 806 to indicate the target cell configuration as at least one of ICBM, dynamic switching, and LTM SCC with a higher chance of success than in the absence of any such resource availability report, because the CU-CP 806 knows, at least in the most recently received resource availability report, that the second DU 804 has available the indicated one or more ICBM, dynamic switching, and LTM SCCs.

[0136] Figure 8c An implementation is illustrated in which the request to the second DU 804 includes the CU-CP 806 indicating the target cell configuration to the second DU 804. Figure 8c As shown in , the target cell configuration may be sent 846 to the second DU 804 in a UE context setup request message. Figure 8c It is also shown that the second DU 804 sends 848 a UE context setup response message to the CU-CP 806 .

[0137] Reference again Figure 7a , the CU-CP 806 notifies 714 the serving DU 804 of at least one target cell prepared by LTM by identifying each of the one or more target cells prepared by LTM and including information about each of the one or more target DUs. In the inter-DU LTM scenario, one or more of the at least one target cell prepared by LTM belongs to a different DU than the serving DU 802. For example, referring to Figure 6bIn the system, the serving DU may be a small cell 626 of a macro 1DU 628a, and one or more of the target cells may be one or more small cells 626 of a macro 2DU 628b and / or a macro 3DU 628c.

[0138] The notification 714 to the serving DU 802 may include the CU-CP 806 sending a UE context modification request message to the serving DU 802 using the F1 communication interface previously established 702. For each target DU in the one or more target DUs, the UE context modification request message may include cell identification information (e.g., a unique cell ID identifying the target DU, such as a physical cell identifier (PCI)), or an index corresponding to the cell ID.

[0139] In response to being notified 714 of at least one LTM prepared target DU cell, the service DU 802 stores the received information about the at least one LTM target cell, for example, storing a list of (multiple) LTM prepared target cells. Similarly, in response to being notified 714 of at least one target DU 804, the service DU 802 can use the F1 communication interface previously established 702 to send a UE context modification response message to the CU-CP 806. The UE context modification response message may include merged cell group configuration information for each of the one or more target cells identified by the CU-CP 806 to the UE. The UE context modification request message and the UE context modification response message are each defined by 3GPP. Therefore, the service DU 802 can receive information about at least one target cell from the CU-CP 806, and can confirm receipt to the CU-CP 806 using the message that has been sent for HO according to the 3GPP standard.

[0140] In some implementations, the notification 714 to the serving DU 802 may include the CU-CP 806 indicating the target cell configuration to the serving DU 802. As described above, the indication of the target cell configuration may be at least one of ICBM, dynamic conversion, and LTM SCC. For example, the indicated target cell configuration may be ICBM. For another example, the indicated target cell configuration may also be dynamic conversion. For another example, the indicated target cell configuration may be LTM SCC. For another example, the indicated target cell configuration may be ICBM and dynamic conversion. For another example, the indicated target cell configuration may be LLM SCC and dynamic conversion.

[0141] Figure 8c An implementation is illustrated in which the notification 714 to the serving DU 802 includes the CU-CP 806 indicating the target cell configuration to the serving DU 802. Figure 8cAs shown in , the target cell configuration may be sent 842 to the serving DU 802 in a UE context modification request message. Figure 8c It is also shown that the serving DU 802 sends 842 a UE context modification response message to the CU-CP 806 .

[0142] Reference again Figure 7a In response to receiving the UE context modification response message, the CU-CP 806 may send an RRC reconfiguration message to the UE in accordance with the 3GPP standard. The RRC reconfiguration message includes LTM target cell configuration information, such as information provided from the target DU 804 to the CU-CP 806 in the sent UE context establishment response message.

[0143] In response to receiving the target cell configuration in the RRC reconfiguration message, the UE may send an L1 measurement report according to the 3GPP standard to the serving DU 802. The L1 measurement report provides the serving DU 802 with UE-measured radio condition information of the configured target cell.

[0144] In response to receiving the L1 measurement report sent from the UE, the serving cell 802 selects 716 a target cell from the one or more LTM prepared target cells identified to the serving DU 802. In the illustrated implementation, there is only one target cell (target DU 804) identified by the CU-CP 806 to the serving DU 802 as an LTM prepared target cell, so the selection 716 of the serving cell is straightforward, with the serving DU 802 selecting 716 the target DU 806. If there are multiple LTM prepared target cells at the serving DU 802 that meet the handover criteria, the serving DU 802 may select the target cell in any of a variety of ways, including selecting according to the conventional procedures of 3GPP.

[0145] In an implementation where the CU-CP 806 identifies multiple target cells to the serving DU 802, the target cell selection 716 of the serving cell may include determining which one or more of the multiple target cells have a radio quality above a predetermined threshold radio quality. The predetermined threshold radio quality is defined by the radio condition of the UE received from the UE by the serving DU 802 in an L1 measurement report. Therefore, when selecting 716 a target cell for HO, the serving DU 802 may take into account the specific needs of the specific UE involved in the HO. In addition, the L1 measurement report sent by the UE to the serving DU 802 may report the L1 measurement of each of the multiple target cells, which may include a reference signal received power (RSRP) defined by 3GPP, and the UE knows that the identities of these target cells have been provided to the UE by the CU-CP 806 in the RRC reconfiguration message. Therefore, the serving DU 802 may analyze the L1 measurement report received from the UE to determine which one or more of the multiple target cells have a radio quality above the predetermined threshold radio quality.

[0146] If only one of the multiple target cells meets the radio condition of the UE, for example, only one of the target cells has a radio quality higher than a predetermined threshold radio quality, the serving cell 802 selects 716 the target cell. If more than one of the multiple target cells meet the radio condition of the UE, for example, the radio quality of the target cells are all higher than a predetermined threshold radio quality, any one of the target cells can meet the needs of the UE, and one of the target cells may be selected randomly or according to another desired criterion.

[0147] In selecting 716 a target cell (eg, Figure 8a 804 in the illustrated implementation of the UE), the serving DU 802 triggers 718 a serving cell change to the selected 716 target cell. Triggering 718 the serving cell change may include the serving DU 802 sending a MAC CE to the UE, the MAC CE including a serving cell change command and identifying the selected 716 target cell to the UE, for example, by a PCI or other identifier.

[0148] The reception of the MAC CE by the UE indicates to the UE that the identified target cell (eg, Figures 8a to 8d804 in the illustrated implementation) performs an LTM service cell change (SCC). Therefore, in response to receiving a MAC CE from the serving cell 802, the UE starts 720 a HO to the target cell. The HO may be performed according to the 3GPP standard. In response to the UE accessing the target cell, the target DU 804 may send a service cell change notification to the CU-CP 806 via the F1 communication interface previously established 704, the service cell change notification identifying the target DU 804 as a new current service cell for at least one served UE, for example, by a unique identifier according to 3GPP. Similarly, in response to receiving a MAC CE from the serving cell 802, the UE may send an RRC reconfiguration confirmation message to the CU-CP 806. Thus, the CU-CP 806 receives confirmation from the UE via an RRC reconfiguration confirmation message indicating a successful RRC reconfiguration at the UE, and receives confirmation from the target DU 804 via a serving cell change notification that the target DU 804 is now providing the UE with at least one service that has been switched from the serving DU 802.

[0149] In some implementations, such as described above with respect to Figures 7a to 8d In various implementations discussed, the CU-CP receives data related to the HO of at least one service of the UE from the DU. In other implementations, the DUs of the base station may directly share their TA information with each other, so that the first DU receives data related to the HO of at least one service of the UE from at least one other DU. Such DU-to-DU communication is not possible in 5G wireless communication systems, but will be possible in 6G or higher wireless communication systems. In implementations in which the first DU receives data from at least one other DU, the first DU may perform the same operations as described above with respect to Figures 7a to 8d The CU-CP 806 of the embodiment of the present invention performs similar operations as discussed above, and considering the data, requests one or more DUs of at least one other DU to prepare at least one LTM target cell for HO of at least one service for the UE.

[0150] use Figure 7b and Figure 8aIn an implementation (e.g., for an implementation in which DU-to-DU communication can be performed), instead of the first DU 802 sending TA information for all beams / beam groups for each cell of the first DU 802 to the CU-CP 806, the first DU 802 sends the TA information to the second DU 804; and instead of the second DU 804 sending TA information for all beams / beam groups for each cell of the second DU 804 to the CU-CP 806, the first DU 802 sends the TA information to the first DU 802. In addition, instead of the CU-CP 806 selecting a configuration and requesting the second DU 804 to prepare at least one target cell according to the selected configuration, the first DU 802 will perform such selection and request. DU-to-DU transmission of TA information will not occur during establishment of the F1 communication interface because, as described above, the F1 communication interface is used for CU-DU communication. Instead, DU-to-DU transmission of TA information may occur during establishment of a communication interface between the first DU 802 and the second DU 804, as appropriate, according to a standard associated with a wireless communication system in which the first DU 802 and the second DU 804 are configured to communicate.

[0151] Fig. 9 The diagram shows the Figures 8a to 8d 802, 804 of the DU 900. Fig. 9 As shown in , DU 900 includes memory 902, processor 904, communicator 906, and configuration management controller 908. Communicator 906 is configured to communicate internally between internal hardware components of DU 900 and to communicate with external devices via one or more networks. Communicator 906 may include electronic circuits specific to a standard that enables wired or wireless communications. Configuration management controller 908 is configured to perform the configuration selection discussed above, and memory 900 is configured to store configurations therein. Multiple configurations may be stored in memory 900, one configuration per UE, so that DU 900 maintains configurations for multiple UEs. Although Fig. 9 The hardware components of DU 900 are shown, but other implementations of DU 900 are possible. For example, DU 900 may include fewer or more components. One or more components may be combined together to perform the same or substantially similar delay management technical features.

[0152] In some implementations, the current subject matter can be configured to be implemented in system 1000, such as Fig.10. System 1000 may include one or more of processor 1010, memory 1020, storage device 1030, and input / output device 1040. Each of components 1010, 1020, 1030, and 1040 may be interconnected using system bus 1050. Processor 1010 may be configured to process instructions for execution within system 600. In some implementations, processor 1010 may be a single-threaded processor. In alternative implementations, processor 1010 may be a multi-threaded processor. Processor 1010 may also be configured to process instructions stored in memory 1020 or on storage device 1030, including receiving or sending information through input / output device 1040. Memory 1020 may store information within system 1000. In some implementations, memory 1020 may be a computer-readable medium. In alternative implementations, memory 1020 may be a volatile memory unit. In some other implementations, the memory 1020 may be a non-volatile memory unit. The storage device 1030 may be capable of providing mass storage for the system 1000. In some implementations, the storage device 1030 may be a computer-readable medium. In alternative implementations, the storage device 1030 may be a floppy disk device, a hard disk device, an optical disk device, a tape device, a non-volatile solid-state memory, or any other type of storage device. The input / output device 1040 may be configured to provide input / output operations for the system 1000. In some implementations, the input / output device 1040 may include a keyboard and / or a pointing device. In alternative implementations, the input / output device 1040 may include a display unit for displaying a graphical user interface.

[0153] Fig.11 An exemplary method 1100 for configuration selection enhancements for LTM according to some implementations of the current subject matter is illustrated. For example, the method 1100 may use Figures 6a to 9 The implementation shown and described in .

[0154] The method 1100 includes receiving 1102 data at a CU-CP of a base station from a first DU of the base station, the data being related to preparing an LTM HO configuration for at least one service for a UE. The method also includes, after receiving the data, requesting 1104 by the CU-CP a second DU of the base station to prepare at least one LTM target cell configuration for HO for at least one service for the UE taking into account the data.

[0155] In some implementations, the present subject matter can include one or more of the following optional features.

[0156] In some implementations, the data may include: timing advance information for each of the multiple cells of the DU. In addition, the CU-CP may receive the data during the process of establishing the F1 communication interface between the CU-CP and the first DU, and / or the CU-CP may receive the data in the F1 establishment request message sent from the first DU to the CU-CP; or, the timing advance information may include: average timing advance information for each of the multiple beams or beam groups of the multiple cells of the second DU for a given reference signal received power (RSRP) value, and before the CU-CP receives a message from the first DU that the UE needs a service change, the CU-CP may receive the average timing advance information from the first DU, and / or the CU-CP may periodically receive the data in a non-UE-related process between the CU-CP and the first DU.

[0157] In some implementations, receiving 1102 may include: before the CU-CP receives a message from the first DU that the UE requires a service change, the CU-CP periodically receives the data from the first DU, and the method may also include: using machine learning at the CU-CP to formulate a HO strategy based at least in part on the received data. In addition, the data may include data about at least one of the following items: the type of UE, the speed of the UE, at least one service accessed by the UE at the first DU, and dynamic switching between the first cell and the second cell; and / or the method may also include: at the CU-CP, from the first DU that currently serves the UE for at least one service, receiving performance data about the first DU's service to the UE; and the request may request the second DU to: prepare at least one LTM target cell while also taking into account the data received from the first DU.

[0158] In some implementations, the first DU may include at least one cell, the data may include resource availability of the at least one cell, and the receiving may include: before the CU-CP receives a message from the first DU that currently serves the UE for at least one service that a UE requires a service change, the CU-CP periodically receives resource availability from the first DU; and / or the resource availability may include availability at each of the at least one cell for the following items: inter-cell beam management (ICBM), LTM service cell change (SCC) with dynamic switching, multiple transmission reception points (mTRP), and LTM SCC.

[0159] In some implementations, the request 1102 may include sending an indication from the CU-CP to the second DU that the target cell configuration is at least one of ICBM, dynamic switching, and LTM SCC.

[0160] In some implementations, the CU-CP may receive the data from the first DU before the CU-CP receives a message from the first DU currently serving the UE for at least one service that the UE requires a service change.

[0161] In some implementations, the method 1100 may further include: selecting, at the CU-CP, a target cell configuration based at least in part on the received data.

[0162] In some implementations, a base station can have a disaggregated architecture.

[0163] In some implementations, the base station may include a NG-RAN node, which includes a gNodeB or an ng-eNodeB.

[0164] In some implementations, a base station may include at least one processor and may include at least one non-transitory storage medium storing instructions that, when executed by the at least one processor, cause the at least one processor to perform method 1100 .

[0165] The systems and methods disclosed herein can be embodied in various forms, including, for example, data processors, such as computers, which also include databases, digital electronic circuit systems, firmware, software, or combinations thereof. In addition, the above-mentioned features and other aspects and principles of the implementations of the present disclosure can be implemented in various environments. Such environments and related applications can be specially constructed to perform various processes and operations according to the disclosed implementations, or they can include general-purpose computers or computing platforms that are selectively activated or reconfigured by code to provide necessary functions. The processes disclosed herein have no inherent relationship with any particular computer, network, architecture, environment, or other device, and can be implemented by a suitable combination of hardware, software, and / or firmware. For example, various general-purpose machines can be used with programs written according to the teachings of the disclosed implementations, or it can be more convenient to build special devices or systems to perform the required methods and techniques.

[0166] The systems and methods disclosed herein may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or a propagated signal, for execution by a data processing apparatus (e.g., a programmable processor, a computer, or multiple computers) or for controlling its operation. The computer program may be written in any form of programming language, including compiled or interpreted languages, and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for a computing environment. The computer program may be deployed to be executed on one or more computers, which are located at one site or distributed between multiple sites and interconnected by a communication network.

[0167] As used herein, the term "user" may refer to any entity, including a person or a computer.

[0168] Although in some cases, ordinal numbers such as first, second, etc. can be related to order; as used in this document, ordinal numbers do not necessarily indicate order. For example, ordinal numbers can only be used to distinguish one item from another item. For example, to distinguish a first event from a second event, but do not need to imply any time order or fixed reference system (such that the first event in one paragraph of the specification can be different from the first event in another paragraph of the specification).

[0169] The above description is intended to illustrate but not limit the scope of the present invention, which is defined by the scope of the appended claims. Other implementations are within the scope of the following claims.

[0170] These computer programs (which may also be referred to as programs, software, software applications, applications, components or codes) include machine instructions for programmable processors and can be implemented using high-level procedural and / or object-oriented programming languages ​​and / or assembly / machine languages. As used herein, the term "machine-readable medium" refers to any computer program product, device and / or equipment for providing machine instructions and / or data to a programmable processor, such as, for example, a disk, an optical disk, a memory and a programmable logic device (PLD), including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor. A machine-readable medium can store such machine instructions in a non-transient manner, such as, for example, a non-transient solid-state memory or a magnetic hard drive or any equivalent storage medium. A machine-readable medium can alternatively or additionally store such machine instructions in a transient manner, such as, for example, a processor cache or other random access memory associated with one or more physical processor cores.

[0171] To provide interaction with a user, the subject matter described herein can be implemented on a computer having a display device for displaying information to the user, such as, for example, a cathode ray tube (CRT) or a liquid crystal display (LCD) display; and a keyboard and pointing device, such as, for example, a mouse or trackball, through which the user can provide input to the computer. Other types of devices may also be used to provide interaction with the user. For example, the feedback provided to the user may be any form of sensory feedback, such as, for example, visual feedback, auditory feedback, or tactile feedback; and the input from the user may be received in any form, including but not limited to acoustic, voice, or tactile input.

[0172] The subject matter described herein can be implemented in a computing system that includes a back-end component, such as one or more data servers, for example; or includes a middleware component, such as one or more application servers, for example; or includes a front-end component, such as one or more client computers with a graphical user interface or a web browser, for example, through which a user can interact with an implementation of the subject matter described herein; or includes any combination of such back-end components, middleware components, or front-end components. The components of the system can be interconnected by digital data communication of any form or medium, such as, for example, a communication network. Examples of communication networks include, but are not limited to, a local area network (LAN), a wide area network (WAN), and the Internet.

[0173] A computing system may include clients and servers. Clients and servers are typically (but not limited to) remote from each other and typically interact through a communication network. The relationship of client and server arises from computer programs running on the respective computers and having a client-server relationship to each other.

[0174] The implementations set forth in the above description do not represent all implementations consistent with the subject matter described herein. Instead, they are merely some examples consistent with aspects related to the described subject matter. Although some variants are described in detail above, other modifications or additions are also possible. In particular, in addition to those features and / or variants described herein, other features and / or variants may also be provided. For example, the above implementations may be directed to various combinations and sub-combinations of the disclosed features, and / or combinations and sub-combinations of the above-mentioned several other features. In addition, the logical flows described in the accompanying drawings and / or herein do not necessarily require the specific order shown or in order to achieve the desired results. Other implementations may be within the scope of the following claims.

Claims

1. A device comprising: at least one processor; as well as at least one non-transitory storage medium storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations comprising: receiving, at a centralized unit control plane (CU-CP) of a base station, data from a first distributed unit (DU) of the base station, the data relating to preparing a layer 1 / layer 2 triggered mobility (LTM) handover (HO) configuration for at least one service of a user equipment (UE), and After receiving the data, the CU-CP requests a second DU of the base station to prepare at least one LTM target cell configuration for the HO for the at least one service of the UE taking into account the data.

2. The apparatus according to claim 1, wherein the data comprises: Timing advance information for each of the plurality of cells of the second DU. 3 . The apparatus of claim 2 , wherein the CU-CP receives the data in a process of establishing an F1 communication interface between the CU-CP and the first DU. 4 . The apparatus of claim 3 , wherein the CU-CP receives the data in an F1 setup request message sent from the first DU to the CU-CP.

5. The apparatus according to claim 2, wherein the timing advance information comprises: average timing advance information for a given reference signal received power (RSRP) value for each of a plurality of beams or beam groups of a plurality of cells of the second DU; and Before the CU-CP receives a message from the first DU indicating that the UE needs a service change, the CU-CP receives the average timing advance information from the first DU. 6 . The apparatus according to claim 5 , wherein the CU-CP periodically receives the data in a non-UE-related process between the CU-CP and the first DU.

7. The apparatus of claim 1, wherein the receiving comprises: Before the CU-CP receives a message from the first DU that the UE needs a service change, the CU-CP periodically receives the data from the first DU; and The operations also include developing a HO strategy using machine learning at the CU-CP based at least in part on the received data.

8. The apparatus of claim 7, wherein the data comprises data regarding at least one of: The type of the UE, The speed of the UE, at least one service accessed by the UE at the first DU, and Dynamic switching between the first cell and the second cell.

9. The apparatus of claim 7, wherein the operations further comprise: receiving, at the CU-CP, performance data on service provided by the first DU to the UE from the first DU currently serving the UE for the at least one service; and The request requests the second DU to prepare the at least one LTM target cell also taking into account the data received from the first DU.

10. The apparatus of claim 1, wherein the first DU comprises at least one cell; The data comprises resource availability of the at least one cell; and The receiving comprises: Before the CU-CP receives a message from the first DU currently serving the UE for the at least one service that the UE requires a service change, the CU-CP periodically receives the resource availability from the first DU.

11. The apparatus of claim 10, wherein the resource availability comprises availability at each of the at least one cell for: inter-cell beam management (ICBM), LTM serving cell change (SCC) with dynamic switching, multiple transmission reception points (mTRP), and LTM SCC.

12. The apparatus of claim 1, wherein the request comprises sending an indication from the CU-CP to the second DU that a target cell configuration is at least one of inter-cell beam management (ICBM), LTM serving cell change (SCC) with dynamic switching, and LTM SCC.

13. The apparatus of claim 1, wherein the CU-CP receives the data from the first DU before the CU-CP receives a message from the first DU currently serving the UE for the at least one service that the UE requires a service change.

14. The apparatus of claim 1, wherein the operations further comprise: At the CU-CP, a target cell configuration is selected based at least in part on the received data.

15. The apparatus of claim 1, wherein the base station has a disaggregated architecture.

16. The apparatus of claim 1, wherein the base station comprises a next generation radio access network (NG-RAN) node, the NG-RAN node comprising a gNodeB or an ng-eNodeB.

17. The apparatus of claim 1, wherein the base station comprises the at least one processor and the at least one non-transitory storage medium.

18. At least one non-transitory storage medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform operations comprising: receiving, at a centralized unit control plane (CU-CP) of a base station, data from a first distributed unit (DU) of the base station, the data relating to preparing a layer 1 / layer 2 triggered mobility (LTM) handover (HO) configuration for at least one service of a user equipment (UE), and After receiving the data, the CU-CP requests a second DU of the base station to prepare at least one LTM target cell configuration for the HO for the at least one service of the UE taking into account the data.

19. A computer-implemented method comprising: receiving, at a centralized unit control plane (CU-CP) of a base station, data from a first distributed unit (DU) of the base station, the data relating to preparing a layer 1 / layer 2 triggered mobility (LTM) handover (HO) configuration for at least one service of a user equipment (UE), and After receiving the data, the CU-CP requests a second DU of the base station to prepare at least one LTM target cell configuration for the HO for the at least one service of the UE taking into account the data.

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