WO2023164617A1

WO2023164617A1 - Load balancing among user plane entities of a central unit of a base station

Info

Publication number: WO2023164617A1
Application number: PCT/US2023/063225
Authority: WO
Inventors: Shiva Prakash; Vagish Srinivasamurthy; Veeresh Salankimatt; Irfaan Ahamed SALAHUDDEEN; James J Ni
Original assignee: Commscope Technologies Llc
Priority date: 2022-02-25
Filing date: 2023-02-24
Publication date: 2023-08-31

Abstract

The present disclosure describes techniques for load balancing among user-plane entities of a central unit within a base station (BS). In one embodiment, a method comprises receiving, by a primary node of the BS, a connection request for a UE entering a cell supported by the BS. The method further comprises determining, by the primary node: a cell load corresponding to the cell for each of the secondary nodes of the BS, the cell load for a secondary node indicative of a load applied by the cell on the secondary node; and a total load experienced by each of the second nodes. The method further comprises selecting, by the primary node, a secondary node for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell; and a plurality of total loads corresponding to the plurality of secondary nodes.

Description

LOAD BALANCING AMONG USER PLANE ENTITIES OF A CENTRAL UNIT OF A

BASE STATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to IN Provisional Application No. 202241010297, filed on February 25, 2022, and titled “LOAD BALANCING AMONG USER PLANE ENTITIES OF A CENTRAL UNIT OF A BASE STATION,” the contents of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

[0002] The present disclosure in general relates to wireless communication. More particularly, but not exclusively, the present disclosure relates to techniques of load balancing among user plane entities of a central unit of a base station.

BACKGROUND

[0003] A Fifth Generation (5G) New Radio (NR) base station (also referred to as a “gNodeB” or “gNB”) is typically partitioned into one or more central unit entities (CUs), one or more distributed unit entities (DUs), and one or more radio units (RUs). The CUs, DUs, and RUs are inter-connected with each other via different interfaces and can be deployed in different configurations. Each CU is typically further partitioned into one or more controlplane entities and one or more user-plane entities that handle the control-plane and user-plane processing of the CU, respectively. Each such control-plane CU entity is also referred to as a “CU-CP” and each such user-plane CU entity is also referred to as a “CU-UP.”

[0004] In one configuration, a gNB consists of a CU-CP, multiple CU-UPs, multiple DUs, and multiple RUs. The DUs and RUs may be interconnected via a fronthaul network. The gNB may support a plurality of cells and the RUs can be used by the gNB for providing wireless services to user equipment (UEs) of the plurality of cells. For instance, the RUs can be used by the gNB to wirelessly transmit downlink data to the UEs and receive uplink data wirelessly transmitted by the UEs. When a new UE enters a cell served by the gNB, the UE sends a connection request to the gNB. The gNB, upon receiving the connection request for the UE, may assign a CU-UP entity to provide wireless services to the UE. Particularly, the CU-CP of the gNB may assign a CU-UP entity from the multiple CU-UPs for providing wireless services to the UE.

[0005] However, the 3rd Generation Partnership Project (3GPP) RAN specifications do not specify how a CU-CP is to select a CU-UP from multiple CU-UPs for serving a UE. In other words, the CU-CP is free to select a CU-UP for serving the UE in any manner. However, selection of CU-UPs in a given manner may result in an uneven distribution of UEs across the CU-UPs because some of the CU-UPs may be frequently selected by the CU-CP for serving the UEs, resulting in overload on the selected CU-UPs. On the other hand, some of the CU-UPs may be either rarely selected or never selected for serving the UE, resulting in underutilization of the capacity of the rarely selected CU-UPs. This uneven distribution of UEs may result in imbalance of load on the CU-UPs thereby degrading the overall performance of the gNB.

[0006] The information disclosed in this background section is only for enhancement of understanding of the general background of the disclosure and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY

[0007] One or more shortcomings discussed above are overcome, and additional advantages are provided by the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the disclosure.

[0008] According to an aspect of the present disclosure, methods, apparatus, and non- transitory computer readable media are provided for load balancing among user plane entities of a central unit (CU-UPs).

[0009] In one non-limiting embodiment of the present disclosure, a method includes receiving, by a primary node of a base station (BS), a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS. The method further includes determining, by the primary node, a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node. The method further includes selecting, by the primary node, a secondary node having the least cell load from the plurality of secondary nodes for serving the UE.

[0010] In another non-limiting embodiment of the present disclosure, a method comprises receiving, by a primary node of a base station (BS), a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS. The method further comprises determining, by the primary node, a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node. The method further comprises determining, by the primary node, a total load experienced by each of the plurality of secondary nodes and selecting, by the primary node, a secondary node from the plurality of secondary nodes for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell and a plurality of total loads corresponding to the plurality of secondary nodes.

[0011] In another non-limiting embodiment of the present disclosure, an apparatus comprises a memory and circuitry in communication with the memory and configured to cause a primary node of a base station (BS) to receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS. The circuitry is further configured to cause the primary node to determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, where the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node. The circuitry is further configured to cause the primary node to select a secondary node having the least cell load from the plurality of secondary nodes for serving the UE.

[0012] In another non-limiting embodiment of the present disclosure, an apparatus comprises a memory and circuitry in communication with the memory. The circuitry is configured to cause a primary node of a base station (BS) to receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS. The circuitry is further configured to cause the primary node to determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node. The circuitry is further configured to cause the primary node to determine a total load experienced by each of the plurality of secondary nodes and select a secondary node from the plurality of secondary nodes for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell and a plurality of total loads corresponding to the plurality of secondary nodes.

[0013] In another non-limiting embodiment of the present disclosure, a non-transitory computer readable media stores one or more instructions which, when executed by at least one processor, cause a primary node of a base station (BS) to receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS. The one or more instructions further cause the primary node to determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, where the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node. The one or more instructions further cause the primary node to select a secondary node having the least cell load from the plurality of secondary nodes for serving the UE.

[0014] In another non-limiting embodiment of the present disclosure, a non-transitory computer readable media stores one or more instructions which, when executed by at least one processor, cause a primary node of a base station (BS) to receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS. The one or more instructions further cause the primary node to determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, where the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node. The one or more instructions further cause the primary node to determine a total load experienced by each of the plurality of secondary nodes; and select a secondary node from the plurality of secondary nodes for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell and a plurality of total loads corresponding to the plurality of secondary nodes.

[0015] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Further aspects and advantages of the present disclosure will be readily understood from the following detailed description with reference to the accompanying drawings. Reference numerals have been used to refer to identical or functionally similar elements. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure wherein:

[0017] Figure 1 shows an exemplary embodiment of a radio access network (RAN) communication system 100 with CU-CP and CU-UP separation, in accordance with some embodiments of the present disclosure.

[0018] Figure 2 shows a high-level block diagram of a RAN system 200 implementing a CU- UP selection scheme, in accordance with some embodiments of the present disclosure.

[0019] Figure 3 shows a high-level block diagram of a RAN system 300 implementing another CU-UP selection scheme, in accordance with some embodiments of the present disclosure.

[0020] Figure 4 shows a high-level block diagram of a RAN system 400 implementing yet another CU-UP selection scheme, in accordance with some embodiments of the present disclosure.

[0021] Figure 5 shows a high-level block diagram of a RAN system 500 implementing yet another CU-UP selection scheme, in accordance with some embodiments of the present disclosure.

[0022] Figure 6 shows a high-level block diagram of an apparatus 600 where the load balancing techniques consistent with the present disclosure may be implemented, in accordance with some embodiments of the present disclosure.

[0023] Figure 7 shows a flowchart of an exemplary method 700 for load balancing among central unit user plane (CU-UP) entities, in accordance with some embodiments of the present disclosure.

[0024] Figure 8 shows a flowchart of another exemplary method 800 for load balancing among central unit user plane (CU-UP) entities, in accordance with some embodiments of the present disclosure.

[0025] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of the illustrative systems embodying the principles of the present disclosure. Similarly, it will be appreciated that any flowcharts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION

[0026] In the present document, the word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or implementation of the present disclosure described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0027] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular form disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the disclosure.

[0028] The terms “comprise(s),” “comprising,” “include(s),” or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device, apparatus, system, or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or apparatus or system or method. In other words, one or more elements in a device or system or apparatus preceded by “comprises. . . a” does not, without more constraints, preclude the existence of other elements or additional elements in the system.

[0029] The terms like “CU-CP,” “CU-CP entity,” and “primary node” may be used interchangeably throughout the description. The terms like “CU-UP,” “CU-UP entity,” and “secondary node” may be used interchangeably throughout the description. The terms like “central unit control plane entity” and “control plane entity of central unit” may be interchangeably used throughout the description. The terms like “central unit user plane entity” and “user plane entity of central unit” may be interchangeably used throughout the description. The terms like “cell specific load,” “per cell load,” “cell load,” and “load per CU-UP per cell” may be interchangeably used throughout the description.

[0030] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration of specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense. In the following description, well known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.

[0031] Figure 1 shows a block diagram illustrating one exemplary embodiment of a radio access network (RAN) communication system 100. The system 100 comprises a base station entity 102 that may serve a geographical area or cell 104. The base station entity 102 may also be referred to here as a “base station” or “base station system” (and, which in the context of a fourth generation (4G) Long Term Evolution (LTE) system, may also be referred to as an “evolved NodeB,” “eNodeB,” or “eNB” and, in the context of a fifth generation (5G) New Radio (NR) system, may also be referred to as a “gNodeB” or “gNB”).

[0032] The cell 104 may have at least one UE 106 associated with it. The base station 102 is configured to provide wireless services to the at least one UE 106 served by the associated cell 104. The at least one UE 106 may be any mobile or non-mobile computing device including, but not limited to, a phone (e.g., a cellular phone or smart phone), a pager, a laptop computer, a desktop computer, a wireless handset, a drone, a portable communication device, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a global positioning system device, or any other suitable computing device including a wired or wireless communications interface. In some embodiments of the present disclosure, the at least one UE 106 may be Internet-of-Things (loT)-enabled device including, but not limited to, vehicles or drones configured to communicate with the base station 102 or a core network.

[0033] Unless explicitly stated to the contrary, references to Layer 1, Layer 2, Layer 3, and other or equivalent layers (such as the Physical Layer or the Media Access Control Layer) refer to layers of the particular wireless interface (for example, 4G LTE or 5G NR) used for wirelessly communicating with the at least one UE 106. Furthermore, it is also to be understood that the techniques of the present disclosure can be used in both standalone and non- standalone modes (or other modes developed in the future), and the following description is not intended to be limited to any particular mode. Moreover, although some embodiments are described here as being implemented for use with 5G wireless systems and interfaces, the following description is not intended to be limited to any particular wireless system or interface.

[0034] In the exemplary embodiment of Figure 1, the base station 102 is implemented as a 5G NR gNB 102. In this embodiment, the gNB 102 may be partitioned into a central unit entity (CU) 108, a distributed unit entity (DU) 110, and one or more radio units (RUs) 112. In such a configuration, the CU 108 typically implements Layer 3 and non-time critical Layer 2 functions for the gNB 102. In this embodiment, the CU 108 and the DU 110 are designed to run on or in “cloud” such that they can horizontally and vertically scale computing resources based on traffic demand.

[0035] In the embodiment of Figure 1, the CU 108 is further partitioned into a control -plane entity 114 and one or more user-plane entities 116 that are configured to handle the controlplane and user-plane processing of the CU 108, respectively. The control-plane CU entity 114 may also be referred to as a “CU-CP” 114 or a primary node, and each such user-plane CU entity 116 may also be referred to as a “CU-UP” 116 or a secondary node. The entities CU-CP and CU-UP are interconnected through the “El” interface specified by the relevant 3GPP 5G NR Technical Specifications. Also, in such a configuration, the DU 110 is typically configured to implement time critical Layer 2 functions and at least some of the Layer 1 functions for the gNB 102. In such configurations, each RU 112 is configured to implement the Radio Frequency (RF) interface, as well as the Physical Layer functions for the gNB 102 that are not implemented in the DU 110. Also, each RU 112 includes or is coupled to a respective set of one or more antennas 118 via which downlink RF signals are radiated to the UEs 106 and via which uplink RF signals transmitted by the UEs 106 are received.

[0036] In one implementation (as shown in Figure 1), each RU 112 is remotely located from the DU 110 serving it, for example, the RUs 112 may be deployed at a cell site while the DU 110 is not. Also, in such an implementation, at least one of the RUs 112 may be remotely located from at least one other RU 112 serving the associated cell 104. In another implementation, at least some of the RUs 112 may be co-located with each other, where the respective sets of antennas 118 associated with the RUs 112 are directed to transmit and receive signals from different areas.

[0037] Each RU 112 is communicatively coupled to the DU 110 serving it via a fronthaul network 120. The fronthaul network 120 may be implemented using a switched Ethernet network, in that case each RU 112 and a physical node on which the DU 110 is implemented may include one or more Ethernet network interfaces to couple each RU 112 and the DU physical node to the fronthaul network 120 in order to facilitate communications between the DU 110 and the RUs 112. In one implementation, such Ethernet network interfaces are used for communication between the DU 110 and the RUs 112 over the fronthaul network 120.

[0038] In such an example, the CU 108 is configured to communicate with a core network 122 of an associated wireless operator using an appropriate backhaul network 124 (typically, a public wide area network such as the Internet). In one non-limiting embodiment of the present disclosure, the core network 122 may be a 5G core network in a standalone mode of deployment. The 5G core network may utilize a cloud-aligned, service-based architecture that spans across all 5G functions and interactions including authentication, security, session management, etc. The 5G core network may further emphasize network function virtualization (NFV) as an integral design concept with virtualized software functions. The 5G core network may comprise an Access and Mobility Management Function (AMF) and a User Plane Function (UPF). The AMF of the 5G core network may be communicatively coupled with the gNB 102 via an interface “NG-C” (also known as N2 interface) and the UPF of the 5G core network may be communicatively coupled with the gNB 102 via an interface “NG-U” (also known as N3 interface). In a non-limiting embodiment, NG-C and NG-U interfaces may be logical interfaces.

[0039] In another non-limiting embodiment, the core network 122 may be a long-term evolution evolved packet core (LTE EPC) network in a non-standalone mode of deployment where services are provided using previous generation infrastructure (for example, using existing LTE Evolved Packet Core (EPC)). In non-standalone deployment, an interface SI may exist between the gNB 102 and the LTE EPC. The present disclosure is applicable for standalone and/or non-standalone modes of deployments or other modes of deployments which may be developed in the future.

[0040] Although Figure 1 (and the description set forth below more generally) is described in the context of a 5G architecture in which the base station 102 is partitioned into a CU 108, a DU 110, and at least one RU 112 and some Physical Layer processing is performed in the DU 110 with the remaining Physical Layer processing being performed in the RUs 112, it is to be understood that the techniques described here can be used with other wireless interfaces (for example, 4G LTE) and with other ways of implementing a base station entity (for example, using a conventional baseband band unit (BBU)/remote radio head (RRH) architecture). Accordingly, references to a CU, DU, or RU in this description and associated figures can also be considered to refer more generally to any entity (including, for example, any “base station” or “RAN” entity) implementing any of the functions or features described here as being implemented by a CU, DU, or RU.

[0041] Each CU 108, DU 110, RU 112, CU-CP 114, CU-UP 116, and any of the specific features described herein can be implemented in hardware, software, or combinations of hardware and software, and the various implementations (whether hardware, software, or combinations of hardware and software) can also be referred to generally as “circuitry,” a “circuit,” or “circuits” that is or are configured to implement at least some of the associated functionality. When implemented in software, such software can be implemented in software or firmware executing on one or more suitable programmable processors (or other programmable device) or configuring a programmable device (for example, processors or devices included in or used to implement special-purpose hardware, general-purpose hardware, and/or a virtual platform). In such a software example, the software can comprise program instructions that are stored (or otherwise embodied) on or in an appropriate non- transitory storage medium or media (such as flash or other non-volatile memory, magnetic disc drives, and/or optical disc drives) from which at least a portion of the program instructions are read by the programmable processor or device for execution thereby (and/or for otherwise configuring such processor or device) in order for the processor or device to perform one or more functions described here as being implemented the software. Such hardware or software (or portions thereof) can be implemented in other ways (for example, in an application specific integrated circuit (ASIC), etc.).

[0042] Moreover, each CU 108, DU 110, RU 112, CU-CP 114, CU-UP 116 may be implemented as a physical network function (PNF) (for example, using dedicated physical programmable devices and other circuitry) and/or a virtual network function (VNF) (for example, using one or more general purpose servers (possibly with hardware acceleration) in a scalable cloud environment and in different locations within an operator’s network (for example, in the operator’s “edge cloud” or “central cloud”). Each VNF can be implemented using hardware virtualization, operating system virtualization (also referred to as containerization), and application virtualization as well as various combinations of two or more the preceding. Where containerization is used to implement a VNF, it may also be referred to as a “containerized network function” (CNF).

[0043] For example, in the exemplary embodiment shown in Figure 1, each RU 112 is implemented as a PNF and is deployed in or near a physical location where radio coverage is to be provided and the CU 108 and the DU 110 are implemented using a respective set of one or more VNFs deployed in a distributed manner within one or more clouds (for example, within an “edge” cloud or “central” cloud). However, the present disclosure is not limited thereto, and each of CU 108, DU 110, RU 112, CU-CP 114, CU-UP 116, and any of the specific features described here as being implemented thereby, can be implemented in other ways.

[0044] In the exemplary embodiment of Figure 1, for the sake of simplicity, it has been shown that the RAN system 100 comprises only one base station (gNB) 102, one DU 110, and one cell 104. However, the present disclosure is not limited thereto and in general the RAN system 100 may comprise more than one base station (gNB) 102 connected with each other via an Xn interface. Each base station 102 may comprise more than one CU 108, more than one DU 110, and more than one RU 112 serving more than one cell 104. Each CU 108 may comprise more than one CU-CP 114 and more than one CU-UP 116. The gNB 102 may elastically scale CU-UPs 116 and DUs 110 based on traffic load, for example, when the traffic load is higher, the gNB 102 may add more CU-UPs and/or DUs.

[0045] In a typical gNB configuration, a CU is communicatively coupled with multiple DUs via the Fl interface. Further, a DU is communicatively coupled with multiple RUs via a fronthaul interface. The CU may be divided into a CU-CP and multiple CU-UPs. The CU-CP is communicatively coupled with each of the CU-UPs via an El interface. The CU-CP is communicatively coupled with each of the DUs via an Fl-C interface. Each of the DUs may be communicatively coupled to each of the CU-UPs via an Fl-U interface. When a UE enters a cell supported by the gNB for establishing a connection with the core network, the CU-CP may select a CU-UP from the multiple CU-UPs for serving the UE. The present disclosure discloses the following selection schemes based on which the CU-CP may select a CU-UP from the multiple CU-UPs for serving the UE.

First CU-UP selection scheme:

[0046] Figure 2 shows a high-level block diagram of a RAN system 200 implementing a first CU-UP selection scheme in accordance with some embodiments of the present disclosure. The system 200 of Figure 2 comprises a CU-CP 114 communicatively coupled with a plurality of DUs 110-1, 110-2, 110-3 (collectively represented by reference numeral 110) via an Fl-C interface. The system 200 further comprises a plurality of CU-UPs 116-1, 116-2, 116-3 (collectively represented by reference numeral 116) each being communicatively coupled with the CU-CP 114 via an El interface. Each Du 110-1, 110-2, 110-3 serves a respective cell 104-1, 104-2, 104-3 (collectively represented by reference numeral 104) using a respective set of RUs (collectively represented by reference numeral 112). Particularly, DU 110-1 may use RUs 112-1, 112-2; DU 110-2 may use RUs 112-21, 112-22; and DU 110-3 may use RUs 112-31, 112-32. The cells 104 are used to serve a plurality of UEs 106-1, 106- 2, 106-3, 106-4, 106-5, 106-6 (collectively represented by reference numeral 106). The cell 104-1 may correspond to DU 110-1 and RUs 112-11, 112-12 and serve the UEs 106-1, 106-2, 106-3. The cell 104-2 may correspond to DU 110-2 and RUs 112-21, 112-22 and may serve the UEs 106-4, 106-5. The cell 104-3 may correspond to DU 110-3 and RUs 112-31, 112-32 and may serve the UE 106-6. Although in this embodiment, one DU is serving only one cell, however, the present disclosure is not limited thereto and in general one DU may serve more than one cell. Further, it may be worth noting here that only few relevant components/units have been shown in Figures 2-5 for the sake of simplicity. However, the present disclosure is not limited thereto and in general some or all component/units of the RAN system 100 may be a part of the RAN systems of Figures 2-5.

[0047] In the RAN system 200 of Figure 2, one DU 110 may be served by a single corresponding CU-UP entity 116 via an Fl-U interface, for example, there exists a one-to- one mapping between a DU 110 and a CU-UP 116. In such configurations, the CU-CP 114 pre-selects one CU-UP 116 for each DU 110 and all UEs 106 of a corresponding DU 110 always use the same CU-UP 116. For example, in Figure 2, DU 110-1 may be served only by CU-UP 116-1 and all UEs 106-1, 106-2, 106-3 of the DU 110-1 will always use the CU-UP 116-1. Similarly, all UEs 106-4, 106-5 of the DU 110-2 will be served only by CU-UP 116-2, and all UEs 106-6 of the DU 110-3 will be served only by CU-UP 116-3. A new UE 106 trying to establish a connection with the core network 122 via a particular DU 110 will be served only by a CU-UP 116 that corresponds to the particular DU 110. For example, when a new UE 106-7 entering the cell 104-2 tries to establish a connection with the core network 122 via DU 110-2 using RU 112-21, it will be served only by CU-UP 116-2.

[0048] Though the configuration described in Figure 2 appears to be straightforward, it has some disadvantages. For example, as the number of DUs 110 required to cover a certain geographical area increases, the same number of CU-UPs 116 will be needed to maintain the 1 : 1 mapping between the DUs 110 and CU-UPs 116, which may consume additional computing resources and may result in complex network configuration. Further, outage of any CU-UP entity 116 may render its corresponding DU 110 incapable of serving new UEs 106 until the CU-UP entity 116 is restored and the UEs 106, which are already served by the CU-UP entity 116, may experience Radio Link Failure (for example, these UEs 106 will not have access to the network until the CU-UP entity 116 is restored). In such configurations, when a UE 106 is handed over from one DU 110 to another DU 110 of the same gNB 102 (for example, when a UE moves 106 from one cell 104 served by one DU 110 to another cell 104 served by a different DU 110) then in addition to changing the DU 110, the CU-CP 114 must change the CU-UP 116 for the UE 106, resulting in a complex handover flow.

[0049] Additionally, each CU-UP 116 has a limited capacity (for example, each CU-UP 116 can serve a limited number of UEs 106). As the number of UEs 106 served by a particular DU 110 increases, the capacity of the CU-UP 116 connected to the particular DU 110 needs to be scaled up to serve the additional UEs 106. However, simply increasing the capacity of the individual CU-UP 116 alone may not be an optimal solution. Moreover, the capacity of individual CU-UPs 116 cannot be increased beyond a limit. Thus, there exists a need to overcome some or all or the limitations of the first CU-UP selection scheme.

Second CU-UP selection scheme:

[0050] Figure 3 shows a high-level block diagram of a RAN system 300 implementing a second CU-UP selection scheme in accordance with some embodiments of the present disclosure. The various elements and interconnections as shown in system 300 may be same as the system 200 of Figure 2 except that all DUs 110 may be served by all CU-UPs 116 (for example, there exists a M:N mapping between the DUs 110 and the CU-UPs 116, where M and N are integers with same or different values). In this selection scheme, a UE 106 trying to connect to a particular DU 110 may be randomly served by any of the CU-UPs 116. For example, a new UE 106-8 entering the cell 104-1 to establish the connection with the core network 122 via DU 110-1 using RU 112-12 may be randomly served by any of the CU-UPs 116.

[0051] In the second CU-UP selection scheme, the CU-CP 114 may randomly select any CU- UP 116 from the plurality of CU-UPs 116 for serving the UE 106-8 (without using any specific criteria/metrics), which can result in an uneven distribution of UEs 106 across the CU-UPs 116. This uneven distribution of UEs 106 across the CU-UPs 116 may result in imbalance of load across the CU-UPs 116 thereby degrading quality of service and overall performance of the RAN system 300. For example, due to the random selection of CU-UPs 116, some CU-UPs 116 may be selected more frequently by the CU-CP 114, which can result in overload on the frequently selected CU-UPs 116, while some CU-UPs 116 may be selected less frequently, which can result in underutilization of the capacity of the rarely selected CU- UPs 116.

Third CU-UP selection scheme:

[0052] Figure 4 shows a high-level block diagram of a RAN system 400 implementing a third CU-UP selection scheme in accordance with some embodiments of the present disclosure. In this scheme, the plurality of CU-UPs 116 may be divided into a plurality of groups based on one or more selection policies. Each group may comprise more than one CU-UP 116 that may serve all DUs 110 depending on the selection policies. For each selection policy, one dedicated group of CU-UPs 116 may be allocated from the plurality of groups. In an example, a selection policy may be defined based on a UE subscription class, where high priority UEs 106 may be provided dedicated services by allocating a group of dedicated CU-UPs 116 from the plurality of groups. In another example, another selection policy may be defined based on home and roaming subscriber separation, where roaming subscribers may be provided dedicated services by allocating another group of dedicated CU- UPs 116 from the plurality of groups. In a similar manner, a plurality of selection policies may be defined based on subscription plans, network slicing, a carrier-based separation, Quality of Service (QoS), but not limited thereto. In such a scheme, a UE 106 that fulfills a selection policy may be served by any CU-UP 116 selected from a corresponding group of dedicated CU-UPs 116 and any UE 106 that does not fulfill any selection policy may be served by any CU-UP 116 selected from a group of non-dedicated CU-UPs 116.

[0053] In Figure 4, all DUs 110 may be served by all of the plurality of CU-UPs 116 (for example, there may exist a M:N mapping between the DUs 110 and the CU-UPs 116, where M and N are integers with same or different values). In the exemplary embodiment, the plurality of CU-UPs 116 are divided into two groups (for example, group 1 and group 2), where group 1 comprises three CU-UPs 116-1, 116-2, and 116-3 and group 2 comprises three CU-UPs 116-4, 116-5, and 116-6. For the sake of explanation, it has been shown that group 1 and group 2 comprise an equal number of CU-UPs 116. However, the present disclosure is not limited thereto, and generally different groups may comprise different numbers of CU- UPs 116. Also, for the sake of simplicity only two groups of CU-UPs 116 have been shown in Figure 4. The present disclosure is not limited thereto and in general there can be multiple groups of CU-UPs 116 based on one or more selection policies.

[0054] In an exemplary embodiment, the CU-CP 114 may allocate all high priority UEs 106 connecting with the DUs 110 only to the CU-UPs 116-1, 116-2, 116-3 of group 1 and the remaining UEs 106 to CU-UPs 116-4, 116-5, 116-6 of group 2. For example, a high priority UE 106-9 (for example, an ultra-reliable low latency communication (URLLC) UE) entering the cell 104-2 for establishing a connection with the core network 122 via DU 110-2 using RU 112-22 may be assigned any CU-UP 116-1, 116-2, 116-3 from group 1. Similarly, the UEs 106 that are non-high priority UEs 106 may be served by any CU-UP 116-4, 116-5, 116- 6 from group 2.

[0055] The third scheme is directed to distributing the UEs across a plurality of groups based on one or more selection policies; however, if the CU-UP selection within a group is random, it might result in an uneven distribution of UEs 106 across the CU-UPs 116 within each group. This uneven distribution of UEs 106 may also degrade overall performance of the RAN system 400 (similar to the second scheme).

Fourth CU-UP selection scheme:

[0056] Figure 5 shows a high-level block diagram of a RAN system 500 implementing a fourth CU-UP selection scheme in accordance with some embodiments of the present disclosure. In this scheme, the plurality of CU-UPs 116 may be divided into two sets — namely a first set and a second set, each comprising more than one CU-UP 116. For each of the plurality of DUs 110, the second set may comprise at least one dedicated CU-UP 116 which is configured to serve a corresponding DU 110 based on one or more selection policies. The at least one dedicated CU-UP 116 may serve only certain types of UEs 106 connecting to the corresponding DU 110 depending on the one or more selection policies. The first set may comprise a plurality of CU-UPs 116, which are configured to serve all DUs 110 (for example, there exists a M:N mapping between CU-UPs 116 of the first set and the DUs 110 similar to the second scheme). The UEs 106 that do not fulfill the selection policy of the second set may be served by any of the CU-UPs 116 selected from the first set of CU- UPs 116. For the sake of simplicity, only one instance of the first set has been shown in Figure 5; however, there may be multiple instances of the first set serving different types of UEs 106 depending on one or more selection policies different from the selection policy of the second set. Further, each instance of the first set may have more than one CU-UP 116.

[0057] In an exemplary embodiment, the CU-CP 114 may allocate all high priority UEs 106 connecting with a particular DU 110 only to the corresponding at least one CU-UP 116 of the second set. In this exemplary embodiment, the second set may comprise one CU-UP 116 corresponding to each DU 110 for serving high priority UEs 106. For instance, the second set may comprise three CU-UPs (for example, CU-UPs 116-7, 116-8, and 116-9), where high priority UEs 106 connecting with DU 110-1 via RUs 112-11, 112-12 will be served only by CU-UP 116-7. Similarly, all high priority UEs 106 connecting with DU 110-2 via RUs 112- 21, 112-22 will be served only by CU-UP 116-8, and all high priority UEs 106 connecting with DU 110-3 via RUs 112-31, 112-32 will be served only by CU-UP 116-9. A new high priority UE 106 trying to establish a connection with the core network 122 via a particular DU 110 will be served only by the corresponding dedicated CU-UP 116. For example, when a high priority UE 106-9 connects to cell 104-2 for establishing a connection with the core network 122 via the DU 110-2 using RU 112-22, it will be served only by CU-UP 116-8.

[0058] The UEs 106 that do not fulfill the selection policy of the second set of CU-UPs 116 may be served by any of the CU-UP 116 selected from the first set of CU-UPs comprising CU-UPs 116-1, 116-2, 116-3. For instance, a non-high priority UE 106-10 connecting to cell 104-1 for establishing a connection with the core network 122 via DU 110-1 using RU 112- 11 will be served by a CU-UP 116-1, 116-2, 116-3 randomly selected from the first set of CU-UPs 116, which may result in an uneven distribution of UEs 106 across the CU-UPs 106 within the first set thereby degrading the overall performance of the RAN system 500 (similar to the second scheme).

[0059] In one non-limiting embodiment of the present disclosure, the CU-CP 114 may keep track of one or more metrics for each CU-UP 116. The one or more metrics for a CU-UP 116 may comprise a cell specific load (or “per cell load” or “cell load” or “load per CU-UP per cell”) experienced by the CU-UP 116 and a total load experienced by the CU-UP 116. The cell specific load experienced by a particular CU-UP 116 due to a particular cell may refer to a load applied or added on the CU-UP 116 by the particular cell 104.

[0060] In a non-limiting embodiment, the cell specific load experienced by the particular CU-UP 116 due to the particular cell 104 may be determined based on one or more factors including, but not limited thereto, a number of active UEs 106 of the particular cell 104 that are served by the particular CU-UP 116, a throughput of the particular CU-UP 116 for the particular cell 104, a number of bearers of the UEs 106 of the particular cell 104 that are admitted by the particular CU-UP 116, and multiple-input and multiple-output (MIMO) capabilities of the UEs 106 of the particular cell 104 that are served by the particular CU-UP 116.

[0061] The number of active UEs 106 of the particular cell 104 that are served by the particular CU-UP 116 may also be referred to as the number of active RRC connections. If the particular CU-UP 116 has a large number of active RRC connections of the particular cell 104, then the cell specific load on the particular CU-UP 116 due to the particular cell 104 will also be high. The CU-CP 114 may use the El Application protocol (El-AP) for keeping track of the one or more factors. The El-AP provides signaling services between a CU-CP 114 and CU-UPs 116 of a gNB 102. The signaling may include bearer setup request/response messages exchanged between the CU-CP 114 and the CU-UPs 116 of the gNB 102 as part of El-AP. The CU-CP 114 may calculate the number of bearers of the UEs 106 of the particular cell 104 that are associated with the particular CU-UP 116 based on the bearer context setup request/response messages. The throughput of the particular CU-UP 116 for the particular cell 104 may be estimated using a data usage report provided by the particular CU-UP 116 for the UEs 106 of the particular cell 104 that are associated with the particular CU-UP 116. The data usage report provided by the particular CU-UP 116 may indicate the amount of data transmitted and received by the UEs 106 of the particular cell 104 in a given time.

[0062] The MIMO capability of a UE 106 defines a number of transmit and receive antennas used by the UE 106 for transmitting and receiving data. A 2x2 MIMO UE comprises two antennas for transmitting/receiving two simultaneous data streams. Similarly, a 4x4 MIMO UE comprises four antennas. Each antenna may be used for both transmitting and receiving data. Generally, a UE 106 with higher MIMO capability (for example, a higher number of transmit/receive antennas) adds more load on the serving CU-UP 116 (particular CU-UP 116) because the CU-UP 116 has to transmit/receive a greater number of data streams simultaneously. The one or more factors corresponding to the CU-UPs 116 are continuously monitored/tracked by the CU-CP 114.

[0063] In one non-limiting embodiment, each of the one or more factors may be assigned a weight and the cell specific load for the particular CU-UP 116 (or load per CU-UP 116 per cell) may be computed as a weighted combination of the one or more factors. The cell specific load Mj _k on a particular CU-UP j applied by a cell k may be given by: Mj,_k= i w_tP_iik (1) where,

P_{i k} is factor i for the cell & of a gNB

0 < w_t < 1 denotes the weight assigned to the factor i m denotes the total number of factors used to compute the per cell load K denotes the number of active cells under a gNB

- N denotes the number of active CU-UPs under a gNB

[0064] The factors can be chosen to be included in the weighted combination based on whether w_£ = 0 or 0 < w_£ < 1 , where 0 is for exclusion of a weight and non-zero is for inclusion of the weight. The actual value of the weights can be modified based on a type of deployment. Initially, all of the 'm' factors may be assigned equal weights by default, for example, = 1/m. If more weightage is required for a particular factor, then it is increased proportionally, with the constraint of

^wi = 1 For example, if number of UEs 106 and throughput are considered as the two factors having weights

and w₂ respectively, the value of weight w₂ may be set as w₂ > 1/2 for high traffic intensity deployments or in cases where it is known that the distribution of traffic is uneven across the cells, for example, hotspot scenarios.

[0065] In one non-limiting embodiment, the CU-CP 114 may compute a total load experienced by a particular CU-UP 116 based on one or more factors including, but not limited to, a central processing unit (CPU) load for the particular CU-UP 116 and a summation of a plurality of cell specific loads experienced by the particular CU-UP 116. The CU-CP 114 may compute the summation of the plurality of cell specific loads (assuming that there is a plurality of cells 104 served by the gNB 102) experienced by a particular CU-UP 116 due to the plurality of cells 104. For example, if there are N cells which are supported by the gNB 102 then there will be n values of cell specific loads for each CU-UP 116. The CU- CP 114 may compute a summation of the n values of the cell specific loads for the particular CU-UP 116. In one non-limiting embodiment, the CU-CP 114 may keep track of the CPU load for each CU-UP 116 of the plurality of CU-UPs 116. The CPU load of a particular CU- UP 116 may be determined by monitoring the resource consumption (for example, CPU utilization) of the particular CU-UP 116.

[0066] In one non limiting embodiment, the total load on a CU-UP j is given by any of:

Tj= CPUJJtilisationj (3)

Tj= max ,k=i Mj_k, CPUJJtilisationj') (4) where,

K denotes the number of active cells under a gNB

- N denotes the number of active CU-UPs under a gNB

[0067] The following paragraphs describe techniques/methods for uniformly distributing UEs 106 across different CU-UPs 116 based on the one or more metrics (for example, the cell specific load and total load). Particularly, the following paragraphs describe load balancing techniques for selecting a suitable CU-UP 116 for a UE 106 that is entering in a particular cell 104 of a plurality of cells 104 served by the gNB 102. The selection of the suitable CU- UP 116 may be based on the cell specific load and/or the total load experienced by the CU- UP 116. The methods of load balancing are explained with the help of the RAN system 300 of Figure 3. However, the present disclosure is not limited thereto, and the load balancing methods are equally applicable for Figures 4-5.

[0068] The following paragraphs describe techniques/methods for uniformly distributing UEs across different CU-UPs 116 based on the one or more metrics (for example, the cell specific load and total load). Particularly, the following paragraphs describe load balancing techniques for selecting a suitable CU-UP 116 for a UE 106 that is entering in a particular cell of a plurality of cells served by the gNB 102. The selection of the suitable CU-UP 116 may be based on the cell specific load and/or the total load experienced by the CU-UP 116. The methods of load balancing are explained with the help of the RAN system 300 of Figure 3. However, the present disclosure is not limited thereto, and the load balancing methods are equally applicable for Figures 4-5. Method 1 :

[0069] In a first load balancing method, a UE 106-8, upon entering a particular cell 104-1 of a plurality of cells 104-1, 104-2, 104-3, sends a connection request for establishing a connection with the core network 122 via DU 110-1. A CU-CP 114 of the gNB 102 receives the connection request for the UE 106-8 that is entering the particular cell 104-1 served by DU 110-1 using RU 112-12. The CU-CP 114 then determines a cell specific load corresponding to the particular cell 104-1 on each of a plurality of CU-UPs 116-1, 116-2, 116-3 based on one or more factors defined above. The cell specific load on the particular CU-UP 116 may be indicative of a load added or applied by the particular cell 104-1 on the particular CU-UP 116. The CU-CP 114 is configured to select a CU-UP 116 with the least cell specific load from the plurality of CU-UPs 116-1, 116-2, 116-3 for serving the UE 106-8.

[0070] In one non-limiting embodiment, when the least cell specific load corresponding to the particular cell 104-1 is same for at least two CU-UPs 116 of the plurality of CU-UPs 116- 1, 116-2, 116-3, then the CU-CP 114 is configured to compute a total load for the at least two CU-UPs 116 having the same least cell specific load. The total load for the at least two CU- UPs 116 may be determined based on one or more factors defined above. The CU-CP 114 may then select a CU-UP 116 with the least total load from the at least two CU-UPs 116 having the same least cell specific load for serving the UE 106-8. In one non-limiting embodiment, when the least total load for at least two CU-UPs 116 having the same least cell specific load is also same, then the CU-CP 114 may randomly select a CU-UP 116 from the at least two CU-UPs 116 having the same least cell specific load and the same least total load for serving the UE 106-8.

Method 2:

[0071] In a second load balancing method, a CU-CP 114 of the gNB 102 is configured to select a CU-UP 116 based only on total load. For example, upon receiving a connection request for a UE 106-8 entering a particular cell 104-1 of a plurality of cells 104-1, 104-2, 104-3 (where the particular cell 104-1 is served by DU 110-1 using RU 112-12), the CU-CP 114 is configured to determine a total load for each of a plurality of CU-UPs 116-1, 116-2, 116-3. The total load for each of the plurality of CU-UPs 116-1, 116-2, 116-3 may be determined based on one or more factors defined above. The CU-CP 114 is configured to then select a CU-UP 116 with the least total load from the plurality of CU-UPs 116-1, 116-2, 116-3 for serving the UE 106-8. In one non-limiting embodiment, when the least total load is same for at least two CU-UPs 116 of the plurality of CU-UPs 116-1, 116-2, 116-3, then the CU-CP 114 is configured to randomly select a CU-UP 116 from the at least two CU-UPs 116 having the same least total load for serving the UE 106-8.

[0072] The above-described load balancing methods may be used in conjunction with the above-described CU-UP selection schemes for uniformly distributing UEs 106 across the CU-UPs 116. In the second CU-UP selection scheme, either of the methods (1) and (2) may be used for selecting a particular CU-UP 116 from the plurality of CU-UPs 116 for serving the UE 106-8 that is connecting to a particular DU 110-1. Similarly, in the third CU-UP selection scheme, either of the methods (1) and (2) may be used for balancing load within each group of the plurality of groups. For instance, either of the methods (1) and (2) may be used for selecting a particular CU-UP 116 from a first group of CU-UPs 116-1, 116-2, 116-3 for serving the UE 106-9. Similarly, in the fourth CU-UP selection scheme, either of the methods (1) and (2) may be used for balancing load within the first set which comprises nondedicated CU-UPs 116. For instance, either of the methods (1) and (2) may be used for selecting a particular CU-UP 116 from the first set of CU-UPs 116-1, 116-2, and 116-3 for serving the UE 106-10.

[0073] In one non-limiting embodiment, the CU-CP 114 may use the total load metric for detecting overload on a CU-UP 116. For example, upon determining that the total load on a particular CU-UP 116 is exceeding a threshold limit, the CU-CP 114 may detect that the particular CU-UP 116 is overloaded. Upon detecting the overloading of the particular CU-UP 116, the CU-CP 114 may select another CU-UP 116 for serving new UEs 106 of the overloaded CU-UP 116 based on the one or more policies and the metrics. For instance, the CU-CP 114 may apply load balancing methods (1) or (2) and/or the one or more policies for serving new UEs 106 of the overloaded CU-UP 116.

[0074] The present disclosure provides various technical advantages. For instance, the techniques of the present disclosure balance load on multiple CU-UPs by uniformly distributing UEs across the multiple CU-UPs. In this manner, the techniques of the present disclosure ensure better resource utilization, increased system throughput, and enhanced quality of service. Further, intra-gNB, inter-DU handover call-flow is simplified as the CU- UP can remain the same for a UE that is undergoing handover. Further, the techniques of the present disclosure ensure that the quality of service (QoS) of an ongoing service does not deteriorate (for example, during handover or during failure of CU-UPs), thereby improving the user experience of already admitted UEs.

[0075] Further, the present disclosure provides efficient mechanisms for handling the failure of any CU-UP in the deployments where multiple DUs are served by multiple CU-UPs. Particularly, the failure of any CU-UP may be easily handled without impacting the QoS of UEs served by CU-UP. This may be achieved, for example, by uniformly distributing the UEs of the failed CU-UP across other CU-UPs based on one or more policies and/or the load balancing methods (1) or (2).

[0076] Furthermore, the techniques of the present disclosure provide higher downlink/uplink frequency reuse in deployments where multiple DUs are served by multiple CU-UPs (for example, in the CU-UP selection schemes described with respect to Figures 3-5), thereby improving the overall throughput of the system. In some aspects, the CU-UP selection schemes described with respect to Figures 3-5 perform better in a reuse scenario, for example, because more reuse can be implemented by adding CU-UPs without the need of increasing the capacity of each CU-UP as for the first CU-UP selection scheme described with respect to Figure 2. In general, “downlink frequency reuse” may refer to situations where separate downlink user data intended for different UEs is simultaneously wirelessly transmitted to the UEs using the same physical resource blocks (PRBs) for the same cell.

Likewise, “uplink frequency reuse” may refer to situations where separate uplink user data is simultaneously wirelessly transmitted from different UEs using the same PRBs for the same cell. Typically, frequency reuse may be used when the UEs in reuse together are sufficiently physically separated from each other so that the co-channel interference resulting from the different simultaneous wireless transmissions is sufficiently low.

[0077] Figure 6 illustrates a block diagram 600 of a load balancing apparatus in accordance with some embodiments of the present disclosure. The apparatus 600 may comprise at least one transmitter 602, at least one receiver 604, at least one processor 608, at least one memory 610, at least one interface 612, and at least one antenna 614. The at least one transmitter 602 is configured to transmit data/information to one or more nodes/devices using the antenna 614, and the at least one receiver 604 is configured to receive data/information from the one or more nodes/devices using the antenna 614. The at least one transmitter and receiver may be collectively implemented as a single transceiver module 606. In one non-limiting embodiment, the at least one processor 608 is communicatively coupled with the transceiver 606, memory 610, interface 612, and antenna 614 for implementing the above-described load balancing methods and CU-CP selection schemes.

[0078] The at least one processor 608 may include, but is not restricted to, microprocessors, microcomputers, micro-controllers, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. A processor may also be implemented as a combination of computing devices, for example, a combination of a plurality of microprocessors or any other such configuration. The at least one memory 610 may be communicatively coupled to the at least one processor 608 and may comprise various instructions, the one or more selection policies, data related to per cell loads and total load for each CU-UP, etc. The at least one memory 610 may include a Random- Access Memory (RAM) unit and/or a non-volatile memory unit such as a Read Only Memory (ROM), optical disc drive, magnetic disc drive, flash memory, Electrically Erasable Read Only Memory (EEPROM), a memory space on a server or cloud and so forth. The at least one processor 608 may be configured to execute one or more instructions stored in the memory 610.

[0079] The interface 612 may include a variety of software and hardware interfaces, for example, a web interface, a graphical user interface, an input device-output device (VO) interface, a network interface, and the like. The I/O interfaces may allow the apparatus 600 to communicate with one or more nodes/devices either directly or through other devices. The network interface may allow the apparatus 600 to interact with one or more networks either directly or via any other network.

[0080] In one non-limiting embodiment, the apparatus 600 may be any of: a part of the base station 102, a part of the CU-CP 114, the base station 102, the CU-CP 114, but not limited thereto.

[0081] Figure 7 is a flowchart illustrating an exemplary load balancing method 700 according to an embodiment of the present disclosure. The method 700 is merely provided for exemplary purposes, and embodiments are intended to include or otherwise cover any load balancing methods or procedures.

[0082] The method 700 includes, at block 702, receiving a connection request for a user equipment (UE) 106 entering a particular cell of a plurality of cells 104 supported by the base station (BS) 102. For example, the circuitry may cause the primary node or CU-CP 114 of the BS 102 to receive the connection request for the UE 106. [0083] At block 704, the method 700 includes determining a cell load corresponding to the particular cell for each of a plurality of secondary nodes 116 of the BS 102. The cell load for a secondary node may be an indicative of a load applied by the particular cell on the secondary node. For example, the circuitry may cause the primary node 114 to determine the cell load corresponding to the particular cell for each of the plurality of secondary nodes or CU-UPs 116 of the BS 102.

[0084] At block 706, the method 700 includes selecting a secondary node having the least cell load from the plurality of secondary nodes 116 for serving the UE 106. For example, the circuitry may cause the primary node 114 to select the secondary node having the least cell load from the plurality of secondary nodes 116 for serving the UE 106.

[0085] In one non-limiting embodiment of the present disclosure, when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes 116, the method may further comprise determining a total load for the at least two secondary nodes having the same least cell load and selecting a secondary node having the least total load from the at least two secondary nodes.

[0086] Figure 8 is a flowchart illustrating another exemplary load balancing method 800 according to an embodiment of the present disclosure. The method 800 is merely provided for exemplary purposes, and embodiments are intended to include or otherwise cover any load balancing methods or procedures.

[0087] The method 800 includes, at block 802, receiving a connection request for a user equipment (UE) 106 entering a particular cell of a plurality of cells 104 supported by the base station (BS) 102. For example, the circuitry may cause a primary node 114 of a BS 102 to receive the connection request for the UE 106.

[0088] At block 804, the method 800 includes determining a cell load corresponding to the particular cell for each of a plurality of secondary nodes 116 of the BS 102. The cell load for a secondary node may be an indicative of a load applied/added by the particular cell on the secondary node. For example, the circuitry may cause the primary node 114 to determine the cell load corresponding to the particular cell for each of the plurality of secondary nodes 116 ofthe BS 102.

[0089] In one non-limiting embodiment of the present disclosure, the cell load for a secondary node may be determined based on one or more of: a number of UEs of the particular cell which are served by the secondary node; a throughput of the secondary node for the particular cell; a number of bearers of UEs of the particular cell which are admitted by the secondary node; and MIMO capabilities of UEs of the particular cell which are served by the secondary node.

[0090] At block 806, the method 800 includes determining a total load experienced by each of the plurality of secondary nodes 116. For example, the circuitry may cause the primary node 114 to determine the total load experienced by each of the plurality of secondary nodes 116.

[0091] In one non-limiting embodiment of the present disclosure, the total load for a secondary node may be determined based on at least one of: a central processing unit (CPU) load for the secondary node; and a summation of a plurality of cell loads experienced by the secondary node, where the plurality of cell loads corresponds to the plurality of cells 104 supported by the BS 102.

[0092] At block 808, the method 800 includes selecting a secondary node from the plurality of secondary nodes 116 for serving the UE 106 based on at least one of: a plurality of cell loads corresponding to the particular cell and a plurality of total loads corresponding to the plurality of secondary nodes 116. For example, the circuitry may cause the primary node 114 to select the secondary node from the plurality of secondary nodes 116 for serving the UE 106 based on at least one of: the plurality of cell loads corresponding to the particular cell and the plurality of total loads corresponding to the plurality of secondary nodes 116.

[0093] In one non-limiting embodiment of the present disclosure, the operation of block 808, i.e., selecting a secondary node from the plurality of secondary nodes 116 for serving the UE 106 may comprise selecting a secondary node with the least total load from the plurality of total loads.

[0094] In one non-limiting embodiment of the present disclosure, the operation of block 808, i.e., selecting a secondary node from the plurality of secondary nodes 116 for serving the UE 106 may comprise selecting a secondary node with the least cell load from the plurality of cell loads and, when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes 116, selecting a secondary node with the least total load from the at least two secondary nodes having the same least cell load.

[0095] In one non-limiting embodiment of the present disclosure, the BS 102 may be a next generation base station (gNB), the primary node may be a central unit control plane (CU-CP) entity, the plurality of secondary nodes 116 may correspond to a plurality of central unit user plane (CU-UP) entities, each CU-UP entity may be communicatively coupled with the CU- CP entity.

[0096] In one non-limiting embodiment of the present disclosure, the CU-CP entity may be communicatively coupled with a plurality of distributed units (DUs) 110 of the BS 102 and each of the plurality of CU-UP entities 116 is communicatively coupled with each of the plurality of DUs 110.

[0097] In one non-limiting embodiment of the present disclosure, each of the plurality of DUs 110 may be further connected with at least one dedicated CU-UP entity different from the plurality of CU-UP entities 116. The method may further comprise receiving a connection request for another UE entering a cell and selecting a CU-UP entity from the plurality of CU- UP entities 116 or from the at least one dedicated CU-UP entity based on one or more selection policies. The selection of the CU-UP entity from the plurality of CU-UP entities may be further based on at least one of a plurality of cell loads and a plurality of total loads.

[0098] In one non-limiting embodiment of the present disclosure, the plurality of secondary nodes 116 is configured to serve the UE 106 based on one or more selection policies.

[0099] The above methods 700, 800 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform specific functions or implement specific abstract data types.

[0100] The various blocks of the methods 700, 800 shown in Figures 7-8 have been arranged in a generally sequential manner for ease of explanation. However, it is to be understood that this arrangement is merely exemplary, and it should be recognized that the processing associated with methods 700, 800 (and the blocks shown in Figures 7-8) can occur in a different order (for example, where at least some of the processing associated with the blocks is performed in parallel and/or in an event-driven manner). Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described herein. Furthermore, the methods can be implemented in any suitable hardware, software, firmware, or combination thereof.

[0101] The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component(s) and/or module(s). Generally, where there are operations illustrated in Figures, those operations may have corresponding counterpart means-plus-function components.

[0102] It may be noted here that the subject matter of some or all embodiments described with reference to Figures 1-6 may be relevant for the methods and the same is not repeated for the sake of brevity.

[0103] In a non-limiting embodiment of the present disclosure, one or more non-transitory computer-readable media may be utilized for implementing the embodiments consistent with the present disclosure. A computer-readable media refers to any type of physical memory (such as the memory 610) on which information or data readable by a processor may be stored. Thus, a computer-readable media may store one or more instructions for execution by the at least one processor 608, including instructions for causing the at least one processor 608 to perform steps or stages consistent with the embodiments described herein. The term “computer-readable media” should be understood to include tangible items and exclude carrier waves and transient signals. By way of example, and not limitation, such computer- readable media can comprise Random Access Memory (RAM), Read-Only Memory (ROM), volatile memory, nonvolatile memory, hard drives, Compact Disc (CD) ROMs, Digital Video Disc (DVDs), flash drives, disks, and any other known physical storage media.

[0104] Thus, certain non-limiting embodiments may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer readable media having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For certain non-limiting embodiments, the computer program product may include packaging material.

[0105] As used herein, a phrase referring to “at least one” or “one or more” of a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c. The terms “a”, “an” and “the” mean “one or more”, unless expressly specified otherwise.

[0106] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the disclosed methods and systems. [0107] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the disclosure be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present disclosure are intended to be illustrative, but not limiting, of the scope of the disclosure, which is set forth in the appended claims.

EXAMPLE EMBODIMENTS

[0108] Example 1 includes a method comprising: receiving, by a primary node of a base station (BS), a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS; determining, by the primary node, a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node; determining, by the primary node, a total load experienced by each of the plurality of secondary nodes; and selecting, by the primary node, a secondary node from the plurality of secondary nodes for serving the UE based on at least one of a plurality of cell loads corresponding to the particular cell; and a plurality of total loads corresponding to the plurality of secondary nodes.

[0109] Example 2 includes the method of Example 1, wherein selecting a secondary node from the plurality of secondary nodes for serving the UE comprises: selecting a secondary node with the least cell load from the plurality of cell loads.

[0110] Example 3 includes the method of Example 2, wherein selecting a secondary node from the plurality of secondary nodes for serving the UE further comprises: when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes, selecting a secondary node with the least total load from the at least two secondary nodes having the same least cell load.

[0111] Example 4 includes the method of any of Examples 1-3, wherein the total load for a secondary node is determined based on at least one of: a central processing unit (CPU) load for the secondary node; and a summation of a plurality of cell loads experienced by the secondary node, wherein the plurality of cell loads corresponds to the plurality of cells supported by the BS. [0112] Example 5 includes the method of any of Examples 1-4, wherein the cell load for a secondary node is determined based on one or more of: a number of UEs of the particular cell which are served by the secondary node; a throughput of the secondary node for the particular cell; a number of bearers of UEs of the particular cell which are admitted by the secondary node; and multiple-input-multiple-output (MIMO) capabilities of UEs of the particular cell which are served by the secondary node.

[0113] Example 6 includes the method of any of Examples 1-5, wherein selecting a secondary node from the plurality of secondary nodes for serving the UE comprises: selecting a secondary node with the least total load from the plurality of total loads.

[0114] Example 7 includes the method of any of Examples 1-6, wherein the plurality of secondary nodes is configured to serve the UE based on one or more selection policies.

[0115] Example 8 includes the method of any of Examples 1-7, wherein: the BS is a next generation base station (gNB); the primary node is a central unit control plane (CU-CP) entity; the plurality of secondary nodes corresponds to a plurality of central unit user plane (CU-UP) entities, each CU-UP entity communicatively coupled with the CU-CP entity; the CU-CP entity is communicatively coupled with a plurality of distributed units (DUs) of the BS; and each of the plurality of CU-UP entities is communicatively coupled with each of the plurality of DUs.

[0116] Example 9 includes the method of Example 8, wherein each of the plurality of DUs is further connected with at least one dedicated CU-UP entity different from the plurality of CU-UP entities, the method further comprising: receiving a connection request for a second UE entering a cell; and selecting a CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity for serving the second UE based on one or more selection policies, wherein the selection of the CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity is further based on at least one of a plurality of cell loads and a plurality of total loads.

[0117] Example 10 includes an apparatus comprising: a memory; and circuitry in communication with the memory and configured to cause a primary node of a base station (BS) to: receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS; determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node; determine a total load experienced by each of the plurality of secondary nodes; and select a secondary node from the plurality of secondary nodes for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell; and a plurality of total loads corresponding to the plurality of secondary nodes.

[0118] Example 11 includes the apparatus of Example 10, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the circuitry is configured to cause the primary node to: select a secondary node with the least cell load from the plurality of cell loads.

[0119] Example 12 includes the apparatus of any of Examples 10-11, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the circuitry is further configured to cause the primary node to: when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes, select a secondary node with the least total load from the at least two secondary nodes having the same least cell load.

[0120] Example 13 includes the apparatus of any of Examples 10-12, wherein the total load for a secondary node is determined based on at least one of: a central processing unit (CPU) load for the secondary node; and a summation of a plurality of cell loads experienced by the secondary node, wherein the plurality of cell loads corresponds to the plurality of cells supported by the BS.

[0121] Example 14 includes the apparatus of any of Examples 10-13, wherein the cell load for a secondary node is determined based on one or more of: a number of UEs of the particular cell which are served by the secondary node; a throughput of the secondary node for the particular cell; a number of bearers of UEs of the particular cell which are admitted by the secondary node; and MIMO capabilities of UEs of the particular cell which are served by the secondary node.

[0122] Example 15 includes the apparatus of any of Examples 10-14, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the circuitry is configured to cause the primary node to: select a secondary node with the least total load from the plurality of total loads.

[0123] Example 16 includes the apparatus of any of Examples 10-15, wherein the plurality of secondary nodes is configured to serve the UE based on one or more selection policies.

[0124] Example 17 includes the apparatus of any of Examples 10-16, wherein: the BS is a next generation base station (gNB); the primary node is a central unit control plane (CU-CP) entity; the plurality of secondary nodes corresponds to a plurality of central unit user plane (CU-UP) entities, each CU-UP entity connected with the CU-CP entity; the CU-CP entity is connected with a plurality of distributed units (DUs) of the BS; and each of the plurality of CU-UP entities is connected with each of the plurality of DUs.

[0125] Example 18 includes the apparatus of Example 17, wherein each of the plurality of DUs is further connected with at least one dedicated CU-UP entity different from the plurality of CU-UP entities, the circuitry is further configured to cause the primary node to: receive a connection request for a second UE entering a cell; and select a CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity for serving the second UE based on one or more selection policies, wherein the selection of the CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity is further based on at least one of a plurality of cell loads and a plurality of total loads.

[0126] Example 19 includes a non-transitory computer readable media storing one or more instructions which, when executed by at least one processor, cause a primary node of a base station (BS) to: receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS; determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node; determine a total load experienced by each of the plurality of secondary nodes; and select a secondary node from the plurality of secondary nodes for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell; and a plurality of total loads corresponding to the plurality of secondary nodes.

[0127] Example 20 includes the non-transitory computer readable media of Example 19, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the one or more instructions, when executed by the at least one processor, cause a primary node of the BS to: select a secondary node with the least cell load from the plurality of cell loads; and when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes, select a secondary node with the least total load from the at least two secondary nodes having the same least cell load.

[0128] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention.

Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof

Claims

CLAIMS What is claimed is:

1. A method comprising: receiving, by a primary node of a base station (BS), a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS; determining, by the primary node, a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node; determining, by the primary node, a total load experienced by each of the plurality of secondary nodes; and selecting, by the primary node, a secondary node from the plurality of secondary nodes for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell; and a plurality of total loads corresponding to the plurality of secondary nodes.

2. The method of claim 1, wherein selecting a secondary node from the plurality of secondary nodes for serving the UE comprises: selecting a secondary node with the least cell load from the plurality of cell loads.

3. The method of claim 2, wherein selecting a secondary node from the plurality of secondary nodes for serving the UE further comprises: when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes, selecting a secondary node with the least total load from the at least two secondary nodes having the same least cell load.

4. The method of claim 1, wherein the total load for a secondary node is determined based on at least one of: a central processing unit (CPU) load for the secondary node; and a summation of a plurality of cell loads experienced by the secondary node, wherein the plurality of cell loads corresponds to the plurality of cells supported by the BS.

5. The method of claim 1, wherein the cell load for a secondary node is determined based on one or more of: a number of UEs of the particular cell which are served by the secondary node; a throughput of the secondary node for the particular cell; a number of bearers of UEs of the particular cell which are admitted by the secondary node; and multiple-input-multiple-output (MEMO) capabilities of UEs of the particular cell which are served by the secondary node.

6. The method of claim 1, wherein selecting a secondary node from the plurality of secondary nodes for serving the UE comprises: selecting a secondary node with the least total load from the plurality of total loads.

7. The method of claim 1, wherein the plurality of secondary nodes is configured to serve the UE based on one or more selection policies.

8. The method of claim 1, wherein: the BS is a next generation base station (gNB); the primary node is a central unit control plane (CU-CP) entity; the plurality of secondary nodes corresponds to a plurality of central unit user plane (CU-UP) entities, each CU-UP entity communicatively coupled with the CU-CP entity; the CU-CP entity is communicatively coupled with a plurality of distributed units (DUs) of the BS; and each of the plurality of CU-UP entities is communicatively coupled with each of the plurality of DUs.

9. The method of claim 8, wherein each of the plurality of DUs is further connected with at least one dedicated CU-UP entity different from the plurality of CU-UP entities, the method further comprising: receiving a connection request for a second UE entering a cell; and selecting a CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity for serving the second UE based on one or more selection policies, wherein the selection of the CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity is further based on at least one of a plurality of cell loads and a plurality of total loads.

10. An apparatus comprising: a memory; and circuitry in communication with the memory and configured to cause a primary node of a base station (BS) to: receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS; determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node; determine a total load experienced by each of the plurality of secondary nodes; and select a secondary node from the plurality of secondary nodes for serving the UE based on at least one of a plurality of cell loads corresponding to the particular cell; and a plurality of total loads corresponding to the plurality of secondary nodes.

11. The apparatus of claim 10, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the circuitry is configured to cause the primary node to: select a secondary node with the least cell load from the plurality of cell loads.

12. The apparatus of claim 10, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the circuitry is further configured to cause the primary node to: when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes, select a secondary node with the least total load from the at least two secondary nodes having the same least cell load.

13. The apparatus of claim 10, wherein the total load for a secondary node is determined based on at least one of: a central processing unit (CPU) load for the secondary node; and a summation of a plurality of cell loads experienced by the secondary node, wherein the plurality of cell loads corresponds to the plurality of cells supported by the BS.

14. The apparatus of claim 10, wherein the cell load for a secondary node is determined based on one or more of: a number of UEs of the particular cell which are served by the secondary node; a throughput of the secondary node for the particular cell; a number of bearers of UEs of the particular cell which are admitted by the secondary node; and

MIMO capabilities of UEs of the particular cell which are served by the secondary node.

15. The apparatus of claim 10, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the circuitry is configured to cause the primary node to: select a secondary node with the least total load from the plurality of total loads.

16. The apparatus of claim 10, wherein the plurality of secondary nodes is configured to serve the UE based on one or more selection policies.

17. The apparatus of claim 10, wherein: the BS is a next generation base station (gNB); the primary node is a central unit control plane (CU-CP) entity; the plurality of secondary nodes corresponds to a plurality of central unit user plane (CU-UP) entities, each CU-UP entity connected with the CU-CP entity; the CU-CP entity is connected with a plurality of distributed units (DUs) of the BS; and each of the plurality of CU-UP entities is connected with each of the plurality of DUs.

18. The apparatus of claim 17, wherein each of the plurality of DUs is further connected with at least one dedicated CU-UP entity different from the plurality of CU-UP entities, the circuitry is further configured to cause the primary node to: receive a connection request for a second UE entering a cell; and select a CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity for serving the second UE based on one or more selection policies, wherein the selection of the CU-UP entity from the plurality of CU-UP entities or from the at least one dedicated CU-UP entity is further based on at least one of a plurality of cell loads and a plurality of total loads.

19. A non-transitory computer readable media storing one or more instructions which, when executed by at least one processor, cause a primary node of a base station (BS) to: receive a connection request for a user equipment (UE) entering a particular cell of a plurality of cells supported by the BS; determine a cell load corresponding to the particular cell for each of a plurality of secondary nodes of the BS, wherein the cell load for a secondary node is indicative of a load applied by the particular cell on the secondary node; determine a total load experienced by each of the plurality of secondary nodes; and select a secondary node from the plurality of secondary nodes for serving the UE based on at least one of: a plurality of cell loads corresponding to the particular cell; and a plurality of total loads corresponding to the plurality of secondary nodes.

20. The non-transitory computer readable media of claim 19, wherein for selecting a secondary node from the plurality of secondary nodes for serving the UE, the one or more instructions, when executed by the at least one processor, cause a primary node of the BS to: select a secondary node with the least cell load from the plurality of cell loads; and when the least cell load is same for at least two secondary nodes of the plurality of secondary nodes, select a secondary node with the least total load from the at least two secondary nodes having the same least cell load.