WO2023164617A1 - Équilibrage de charge entre des entités de plan utilisateur d'une unité centrale d'une station de base - Google Patents

Équilibrage de charge entre des entités de plan utilisateur d'une unité centrale d'une station de base Download PDF

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Publication number
WO2023164617A1
WO2023164617A1 PCT/US2023/063225 US2023063225W WO2023164617A1 WO 2023164617 A1 WO2023164617 A1 WO 2023164617A1 US 2023063225 W US2023063225 W US 2023063225W WO 2023164617 A1 WO2023164617 A1 WO 2023164617A1
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Prior art keywords
cell
load
node
secondary node
entity
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PCT/US2023/063225
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English (en)
Inventor
Shiva Prakash
Vagish Srinivasamurthy
Veeresh Salankimatt
Irfaan Ahamed SALAHUDDEEN
James J Ni
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Commscope Technologies Llc
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Publication of WO2023164617A1 publication Critical patent/WO2023164617A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/08—Load balancing or load distribution
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices
    • H04W88/085—Access point devices with remote components
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/08—Load balancing or load distribution
    • H04W28/086—Load balancing or load distribution among access entities

Definitions

  • 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.
  • 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.”
  • 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.
  • 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.
  • 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.
  • the CU-CP of the gNB may assign a CU-UP entity from the multiple CU-UPs for providing wireless services to the UE.
  • 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.
  • the CU-CP is free to select a CU-UP for serving the UE in any manner.
  • 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.
  • 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.
  • CU-UPs central unit
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • RAN radio access network
  • 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.
  • 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.
  • 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.
  • FIG. 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.
  • FIG. 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.
  • FIG. 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.
  • CU-UP central unit user plane
  • FIG. 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.
  • CU-UP central unit user plane
  • CU-CP CU-CP entity
  • primary node CU-CP entity
  • CU-UP CU-UP entity
  • secondary node may be used interchangeably throughout the description.
  • central unit control plane entity and “control plane entity of central unit” may be interchangeably used throughout the description.
  • central unit user plane entity and “user plane entity of central unit” may be interchangeably used throughout the description.
  • cell specific load may be interchangeably used throughout the description.
  • FIG. 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”).
  • 4G Long Term Evolution
  • eNB evolved NodeB
  • gNodeB fifth generation
  • gNodeB fifth generation
  • 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.
  • 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.
  • LoT Internet-of-Things
  • references to Layer 1, Layer 2, Layer 3, and other or equivalent layers 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.
  • 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.
  • 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.
  • the base station 102 is implemented as a 5G NR gNB 102.
  • 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.
  • the CU 108 typically implements Layer 3 and non-time critical Layer 2 functions for the gNB 102.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • RF Radio Frequency
  • 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.
  • 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.
  • Ethernet network interfaces are used for communication between the DU 110 and the RUs 112 over the fronthaul network 120.
  • 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).
  • 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).
  • AMF Access and Mobility Management Function
  • UPF User Plane Function
  • 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).
  • NG-C and NG-U interfaces may be logical interfaces.
  • 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)).
  • LTE EPC long-term evolution evolved packet core
  • EPC existing LTE Evolved Packet Core
  • 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.
  • 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).
  • BBU baseband band unit
  • RRH radio head
  • 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.
  • 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.
  • circuitry a “circuit,” or “circuits” that is or are configured to implement at least some of the associated functionality.
  • 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).
  • 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.
  • an appropriate non- transitory storage medium or media such as flash or other non-volatile memory, magnetic disc drives, and/or optical disc drives
  • Such hardware or software (or portions thereof) can be implemented in other ways (for example, in an application specific integrated circuit (ASIC), etc.).
  • 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”).
  • PNF physical network function
  • VNF virtual network function
  • 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).
  • CNF containerized network function
  • 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).
  • clouds for example, within an “edge” cloud or “central” cloud.
  • 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.
  • the RAN system 100 comprises only one base station (gNB) 102, one DU 110, and one cell 104.
  • 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.
  • a CU is communicatively coupled with multiple DUs via the Fl interface.
  • 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.
  • 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.
  • FIG. 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).
  • DU 110-1 may use RUs 112-1, 112-2;
  • DU 110-2 may use RUs 112-21, 112-22;
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the CU-CP 114 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.
  • 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.
  • FIG. 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).
  • a UE 106 trying to connect to a particular DU 110 may be randomly served by any of the CU-UPs 116.
  • 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.
  • 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.
  • 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.
  • FIG. 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.
  • 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.
  • one dedicated group of CU-UPs 116 may be allocated from the plurality of groups.
  • 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.
  • 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.
  • 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.
  • QoS Quality of Service
  • 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.
  • 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).
  • 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.
  • group 1 and group 2 comprise an equal number of CU-UPs 116.
  • 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.
  • 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.
  • a high priority UE 106-9 for example, an ultra-reliable low latency communication (URLLC) UE
  • URLLC ultra-reliable low latency communication
  • 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.
  • 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).
  • FIG. 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the second set may comprise one CU-UP 116 corresponding to each DU 110 for serving high priority UEs 106.
  • 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.
  • 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.
  • 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).
  • 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.
  • 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.
  • MIMO multiple-input and multiple-output
  • 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.
  • 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.
  • a 4x4 MIMO UE comprises four antennas. Each antenna may be used for both transmitting and receiving data.
  • a UE 106 with higher MIMO capability 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.
  • 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.
  • P i k is factor i for the cell & of a gNB
  • - N denotes the number of active CU-UPs under a gNB
  • weight w i 1
  • the value of weight w 2 may be set as w 2 > 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.
  • 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.
  • the CU- CP 114 may compute a summation of the n values of the cell specific loads for the particular CU-UP 116.
  • 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.
  • the total load on a CU-UP j is given by any of:
  • K denotes the number of active cells under a gNB
  • - N denotes the number of active CU-UPs under a gNB
  • 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 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.
  • the CU-CP 114 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • either of the methods (1) and (2) may be used for balancing load within each group of the plurality of groups.
  • 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.
  • either of the methods (1) and (2) may be used for balancing load within the first set which comprises nondedicated CU-UPs 116.
  • 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.
  • 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.
  • 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.
  • QoS quality of service
  • 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.
  • 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).
  • 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.
  • 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.
  • “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.
  • PRBs physical resource blocks
  • 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.
  • 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.
  • FIG. 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
  • 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.
  • 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.
  • 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.
  • RAM Random- Access Memory
  • ROM Read Only Memory
  • EEPROM Electrically Erasable Read Only Memory
  • the at least one processor 608 may be configured to execute one or more instructions stored in the memory 610.
  • 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.
  • 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.
  • FIG. 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.
  • 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.
  • the circuitry may cause the primary node or CU-CP 114 of the BS 102 to receive the connection request for the UE 106.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the circuitry may cause a primary node 114 of a BS 102 to receive the connection request for the UE 106.
  • 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.
  • 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.
  • 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.
  • the method 800 includes determining a total load experienced by each of the plurality of secondary nodes 116.
  • the circuitry may cause the primary node 114 to determine the total load experienced by each of the plurality of secondary nodes 116.
  • 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.
  • CPU central processing unit
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • gNB next generation base station
  • CU-CP central unit control plane
  • CU-UP central unit user plane
  • 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.
  • DUs distributed units
  • 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.
  • the plurality of secondary nodes 116 is configured to serve the UE 106 based on one or more selection policies.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • RAM Random Access Memory
  • ROM Read-Only Memory
  • volatile memory volatile memory
  • nonvolatile memory nonvolatile memory
  • hard drives Compact Disc (CD) ROMs
  • DVDs Digital Video Disc
  • flash drives disks, and any other known physical storage media.
  • certain non-limiting embodiments may comprise a computer program product for performing the operations presented herein.
  • 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.
  • the computer program product may include packaging material.
  • 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.
  • “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.
  • 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.
  • BS base station
  • UE user equipment
  • 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.
  • 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.
  • 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.
  • CPU central processing unit
  • 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.
  • MIMO multiple-input-multiple-output
  • 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.
  • 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.
  • 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.
  • gNB next generation base station
  • CU-CP central unit control plane
  • CU-UP central unit user plane
  • 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.
  • 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.
  • BS base station
  • UE user equipment
  • 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.
  • 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.
  • 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.
  • CPU central processing unit
  • 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.
  • 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.
  • 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.
  • 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.
  • gNB next generation base station
  • 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
  • DUs distributed units
  • 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.
  • 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.
  • BS base station
  • UE user equipment
  • 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.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente divulgation décrit des techniques d'équilibrage de charge entre des entités de plan utilisateur d'une unité centrale à l'intérieur d'une station de base (BS). Dans un mode de réalisation, un procédé consiste à recevoir, par un nœud principal de la BS, une demande de connexion concernant un UE entrant dans une cellule prise en charge par la BS. Le procédé consiste en outre à déterminer, par le nœud principal : une charge cellulaire correspondant à la cellule pour chacun des nœuds secondaires de la BS, la charge cellulaire pour un nœud secondaire indiquant une charge appliquée par la cellule sur le nœud secondaire ; et une charge totale subie par chacun des nœuds secondaires. Le procédé consiste en outre à sélectionner, par le nœud principal, un nœud secondaire pour desservir l'UE sur la base : d'une pluralité de charges cellulaires correspondant à la cellule particulière ; et/ou d'une pluralité de charges totales correspondant à la pluralité de nœuds secondaires.
PCT/US2023/063225 2022-02-25 2023-02-24 Équilibrage de charge entre des entités de plan utilisateur d'une unité centrale d'une station de base WO2023164617A1 (fr)

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US20200045583A1 (en) * 2018-08-01 2020-02-06 Kt Corporation Method for load management of base station and apparatuses thereof
US20210068183A1 (en) * 2018-01-11 2021-03-04 Samsung Electronics Co., Ltd. Apparatus and method for selecting centralized unit-user plane in wireless communication system
US20210219204A1 (en) * 2018-09-29 2021-07-15 Huawei Technologies Co., Ltd. Load balancing method and apparatus
WO2022005377A1 (fr) * 2020-07-03 2022-01-06 Telefonaktiebolaget Lm Ericsson (Publ) Distribution de rapport de mesure de qoe dans une architecture ran divisée

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US20210068183A1 (en) * 2018-01-11 2021-03-04 Samsung Electronics Co., Ltd. Apparatus and method for selecting centralized unit-user plane in wireless communication system
US20200045583A1 (en) * 2018-08-01 2020-02-06 Kt Corporation Method for load management of base station and apparatuses thereof
US20210219204A1 (en) * 2018-09-29 2021-07-15 Huawei Technologies Co., Ltd. Load balancing method and apparatus
WO2022005377A1 (fr) * 2020-07-03 2022-01-06 Telefonaktiebolaget Lm Ericsson (Publ) Distribution de rapport de mesure de qoe dans une architecture ran divisée

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