Claims:CLAIMS
We Claim:
1. A method for optimizing Physical Cell ID (PCI) assignment in an Open Radio Access Network (O-RAN) (100), comprising:
deploying an optimization service in an rApp (104) and registering the optimization service as a PCI-rApp within a Service Management and Orchestration (SMO) Framework (102), wherein the rApp (104) is in connection with a Non-Real-Time-Radio Access Network Intelligent Controller (Non-RT-RIC) (106) through an interface; and
assigning a listing of unique predefined PCIs (Physical Cell IDs) to operating cells of a selected range after satisfying one or more constraints, wherein the operating cells have neighbour relations.

2. The method as claimed in claim 1 comprising:
assigning procedure successful if an assignment of the PCI to each operating cell completes without using more than the listing of unique predefined PCIs.

3. The method as claimed in claim 1, wherein if any fault is detected or notified from any of the selected range, the rApp (104) identifies a cluster of operating cells around an operating cell generating a fault message and re-assigns the listing of unique predefined PCIs to the cluster of operating cells, representing a faulty cluster, based on the one or more constraints.

4. The method as claimed in claim 1, wherein the one or more constraints are related to a collision, a confusion, and a modulo 3/30 non-overlap between neighbours, and a minimum PCI-reuse distance.

5. The method as claimed in claim 1 comprising using an O1 interface for the O-RAN (100) to get data updates, fault supervision and network configuration, wherein the O1 interface links the SMO (102) to an E2 node (110), where the E2 node creates a measurement job and the SMO (102) subscribes to at least one of a Fault management (FM), a Configuration management (CM), a Performance management (PM) data from the E2 node, wherein the E2 node (110) comprises an Open-Distributed Unit (O-DU) and an Open-Centralized Unit (O-CU).

6. The method as claimed in claim 1 comprising using an O1 interface for the O-RAN (100) to get data updates, fault supervision and network configuration, wherein the O1 interface links the SMO (102) to an O1 interface adapter which links to an E2 node (110), where the E2 node creates a measurement job and the SMO (102) subscribes to at least one of a Fault management (FM), a Configuration management (CM), a Performance management (PM) data from the E2 node, wherein the E2 node (110) comprises an Open-Distributed Unit (O-DU) and an Open-Centralized Unit (O-CU).

7. The method as claimed in claim 1, wherein the rApp (104) consumes network data having CM notification of new cell deployment or neighbour relation change, FM about PCI conflict(s) and PM.

8. The method as claimed in claim 1, wherein the rApp (104) determines a PCI for newly deployed cell or PCI changes to resolve flagged PCI conflicts.

9. The method as claimed in claim 1, wherein the E2 node (110) executes configuration and sends CM change confirmation to the rApp (104).

Dated this 24th March, 2022
Signatures:
Name: Arun Kishore Narasani
Patent Agent (IN/PA-1049) , Description:TECHNICAL FIELD
[0001] The present disclosure relates to a wireless communication network/system, and more specifically, relates to a method and a system for optimizing Physical Cell ID (PCI) assignment in a wireless communication network.

BACKGROUND
[0002] In 5G deployments, each 5G New Radio (NR) cell corresponds to a Physical cell ID (PCI). The PCI is a cell identifier in a physical layer that is used to scramble data to allow user equipments (UEs) to separate information from different base stations or to differentiate cells. However, a UE cannot differentiate between two cells if both have the same PCI and frequency bands, resulting in PCI conflicts such as PCI confusion and PCI collision. In the former, if two neighbour cells have the same PCI, a serving cell will not be able to identify a target cell on receiving a report for handover purposes and in the later, the UE located in a common coverage of two cells may not be able to decode channels of a serving base station.
[0003] For the same, confusion-free and collision-free PCI planning is necessary. Poor or erroneous planning may affect synchronization procedure, demodulation, handover signalling, for example and ultimately degrade network performance. To be precise, for PCI collision avoidance, two neighbour cells must have different PCIs and for PCI confusion avoidance, two neighbour cells of one cell, i.e., the serving cell, must have different PCIs. Further, two neighbour cells should have different PCI modulo 3, 4 and 30.
[0004] Some of the prior art references are given below:
[0005] US20200120724A1 discloses apparatus and methods for physical cell identification within one or more wireless networks. In one embodiment, conflicts in PCI values which may exist within two or more mobile networks (e.g., PLMNs) of respective different operators when unlicensed spectrum is utilized (e.g., according to 3GPP 5G NR-U technology) are resolved. In one implementation, this functionality is provided by specifying one or more mobility-related parameters associated with various UE, such that serving gNBs can determine whether a given UE requires a mobility context, and as such whether it should conduct subsequent RF measurement reporting to report back potential conflicts in PCI it may encounter to the gNB. In one variant, the measurement reporting is configured to comply with 5G NR-U required “listen-before-talk” or LBT protocols; i.e., to measure parameters consistent with the LBT protocols to detect any such PCI-based conflicts.
[0006] ES2813528T3 teaches self-organizing network function interaction. A method, by means of a high-level Self Organization Network function, SON, in a hierarchical structure of functions SON in a network, of interaction with two or more functions SON of a lower level within the hierarchical structure, operating the lower-level SON functions in different cells, comprising: receiving, from the two or more lower-level SON functions, information about the network conditions or the subscriber's activity, including the identity information of the two or more lower-level SON functions and any network optimization actions performed by the two or more lower-level SON functions; analyze the information received from the two or more lower-level SON functions, including consideration of distributed load balancing actions performed by the lower-level SON functions; and perform one or more centralized load balancing actions to optimize the network in response to information analysis, where the high-level SON function is located in a Network Manager, NM, and operates to optimize the overall network, and the two or more lower level SON functions are located in each Network Element, NE, to locally optimize the NE under the control and direction of the higher level SON function.
[0007] While the prior arts cover various solutions for optimizing Physical Cell ID (PCI) assignment, however, these solutions are not scalable and robust and are trapped in a local minima as they are based on neighbour cell relations, thereby resulting in handover failures, delayed downlink synchronization, high Block Error Rate (BLER), decoding failure of physical channels, for example. In light of the above-stated discussion, there is a need to overcome the above-stated disadvantages.

OBJECT OF THE DISCLOSURE
[0008] A principal object of the present disclosure is to provide a method and a system for optimizing Physical Cell ID (PCI) assignment in a wireless communication network.
[0009] Another object of the present disclosure is to implement techniques for PCI assignments such as complete (re-)assignment, incremental assignment and fault management induced local re-assignment.
[0010] Another object of the present disclosure is to execute optimal PCI assignment by an rApp hosted by a Non-Real-Time Radio Access Network Intelligent Controller (non-RT-RIC) in an O-RAN (Open Radio Access Network) compliant architecture at the time of a cell activation or cell topology/configuration change and/or upon receiving a fault management message/notification due to a PCI conflict such as PCI collision and/or PCI confusion.

SUMMARY
[0011] Accordingly, the present disclosure provides a method and a system for optimizing Physical Cell ID (PCI) assignment in a wireless communication network such as an Open Radio Access Network (O-RAN). The method deploys an optimization service in an rApp and registers the optimization service as a PCI-rApp within a Service Management and Orchestration (SMO) framework. The rApp is in connection with a Non-Real-Time-Radio Access Network Intelligent Controller (Non-RT-RIC) through an interface. The method assigns a listing of unique predefined PCIs (Physical Cell IDs) to operating cells of a selected range after satisfying one or more constraints. The one or more constraints are related to a collision, a confusion, and a modulo 3/30 non-overlap between neighbours, and a possibly minimum PCI-reuse distance. The operating cells have neighbour relations, i.e., for a particular operating cell, a set of operating cells are its neighbours. The method further concludes that the procedure has been successful if an assignment of the PCI to each operating cell completes without using more than the listing of unique predefined PCIs.
[0012] If any fault is detected or notified from any of the selected range, the rApp identifies a cluster of operating cells around an operating cell generating a fault message and re-assigns the listing of unique predefined PCIs to the cluster of operating cells, representing a faulty cluster, based on the one or more constraints. As stated above, the one or more constraints are related to the collision, the confusion, and the modulo 3/30 non-overlap between neighbours, and the possibly minimum PCI-reuse distance.
[0013] The method uses an O1 interface for the O-RAN to get data updates, fault supervision and network configuration, wherein the O1 interface links the SMO to an E2 node. The E2 node creates a measurement job and the SMO subscribes to at least one of Fault Management (FM), a Configuration Management (CM), a Performance Management (PM) data from the E2 node. The E2 node comprises an Open-Distributed Unit (O-DU) and an Open-Centralized Unit (O-CU). It should be understood that the O1 interface from the SMO could link to an O1 interface adapter which links to a node with the O-CU and/or the O-DU which may not yet support the O1 interface.
[0014] Herein, the rApp consumes network data having CM notification of new cell deployment or cell(s) with neighbour relation change, FM about PCI conflict(s) and PM. The rApp determines a PCI for newly deployed cell or PCI changes to resolve flagged PCI conflicts. The E2 node executes configuration change and sends CM change confirmation to the rApp.
[0015] These and other aspects herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the invention herein without departing from the spirit thereof.

BRIEF DESCRIPTION OF FIGURES
[0016] The invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the drawings. The invention herein will be better understood from the following description with reference to the drawings, in which:
[0017] FIG. 1 illustrates an O-RAN (Open-Radio Access Network) according to present disclosure.
[0018] FIG. 2 is a sequence diagram for optimizing Physical Cell ID (PCI) assignment in the O-RAN.
[0019] FIG. 2a is a flow diagram illustrating optimized PCI assignment and reassignment techniques.
[0020] FIG. 3 illustrates various hardware components of an rApp for optimizing the PCI assignment.
[0021] FIG. 4 is a flowchart illustrating a method for optimizing the PCI assignment.

DETAILED DESCRIPTION
[0022] In the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be obvious to a person skilled in the art that the invention may be practiced with or without these specific details. In other instances, well known methods, procedures and components have not been described in details so as not to unnecessarily obscure aspects of the invention.
[0023] Furthermore, it will be clear that the invention is not limited to these alternatives only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art, without parting from the scope of the invention.
[0024] The accompanying drawings are used to help easily understand various technical features and it should be understood that the alternatives presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
[0025] Standard networking terms and abbreviation: Active bearer: An active bearer corresponds to tunnel connections between the UE and a packet data network gateway to provide a service.
[0026] QoS Class identifier (QCI): QCI level corresponds to a QoS value required by an active bearer in the UE to provide the service.
[0027] gNB: New Radio (NR) Base stations which have capability to interface with 5G Core named as NG-CN over NG-C/U (NG2/NG3) interface as well as 4G Core known as Evolved Packet Core (EPC) over S1-C/U interface.
[0028] LTE eNB: An LTE eNB is evolved eNodeB that can support connectivity to EPC as well as NG-CN.
[0029] Non-standalone NR: It is a 5G Network deployment configuration, where a gNB needs an LTE eNodeB as an anchor for control plane connectivity to 4G EPC or LTE eNB as anchor for control plane connectivity to NG-CN.
[0030] Standalone NR: It is a 5G Network deployment configuration where gNB does not need any assistance for connectivity to core Network, it can connect by its own to NG-CN over NG2 and NG3 interfaces.
[0031] Non-standalone E-UTRA: It is a 5G Network deployment configuration where the LTE eNB requires a gNB as anchor for control plane connectivity to NG-CN.
[0032] Standalone E-UTRA: It is a typical 4G network deployment where a 4G LTE eNB connects to EPC.
[0033] Xn Interface: It is a logical interface which interconnects the New RAN nodes i.e., it interconnects gNB to gNB and LTE eNB to gNB and vice versa.
[0034] Reference signal received power (RSRP): RSRP may be defined as the linear average over the power contributions (in [W]) of the resource elements that carry cell-specific reference signals within the considered measurement frequency bandwidth.” RSRP may be the power of the LTE Reference Signals spread over the full bandwidth and narrowband.
[0035] Referring now to the drawings, and more particularly to FIGS. 1 through 4.
[0036] FIG. 1 illustrates an O-RAN (Open-Radio Access Network) system (or O-RAN) 100 according to present disclosure.
[0037] A radio access network (RAN) is a part of a telecommunications system which connects individual devices to other parts of a network through radio connections. The RAN provides a connection of user equipment (UE) such as mobile phone or computer with a core network of the telecommunication systems. The RAN is an essential part of access layer in the telecommunication systems which utilizes base stations (such as e node B, g node B) for establishing radio connections. The O-RAN (Open-Radio Access Network) 100 is an evolved version of prior radio access networks, makes the prior radio access networks more open and smarter than previous generations. The O-RAN provides real-time analytics that drive embedded machine learning systems and artificial intelligence back end modules to empower network intelligence. Further, the O-RAN includes virtualized network elements with open and standardized interfaces. The open interfaces are essential to enable smaller vendors and operators to quickly introduce their own services, or enables operators to customize the network to suit their own unique needs. Open interfaces also enable multivendor deployments, enabling a more competitive and vibrant supplier ecosystem. Similarly, open-source software and hardware reference designs enable faster, more democratic and permission-less innovation. Further, the O-RAN introduces a self-driving network by utilizing new learning-based technologies to automate operational network functions. These learning-based technologies make the O-RAN intelligent. Embedded intelligence, applied at both component and network levels, enables dynamic local radio resource allocation and optimizes network wide efficiency. In combination with O-RAN’s open interfaces, AI-optimized closed-loop automation is a new era for network operations.
[0038] The O-RAN 100 may comprise a Service Management and Orchestrator (SMO) (can also be termed as “Service Management and Orchestration Framework”) 102, a Near-Real Time RAN Intelligent Controller (Near-RT-RIC) 108, an E2 node 110 and an Open Cloud (O-Cloud) 112.
[0039] The SMO 102 may be configured to provide SMO functions/services such as data collection and provisioning services of the ORAN 100. The data collection of the SMO 102 may include, for example, data related to a bandwidth of a wireless communication network and at least one of a plurality of user equipments (not shown in figures). That is, the SMO 102 may oversee all the orchestration aspects, management and automation of ORAN elements and resource and supports O1, A1 and O2 interfaces. The SMO 102 logically terminates the O1 and O2 interface.
[0040] A Non-Real Time RAN Intelligent Controller (Non-RT-RIC) 106 may reside in the SMO 102 connected via various internal interfaces and may comprise a Non-RT-RIC Application such as rApp 104 connected/integrated via an R1 interface. rApp is a modular microservice and an independent software plug-in to the Non-RT-RIC 106 deployed to provide functional extensibility to the ORAN by third parties. That is, the Non-RT-RIC 106 may provide different functionalities by using programmable modules as rApp(s), from different operators and vendors. There may be one or more rApps 104 in the Non-RT-RIC 106. Generally, the services delivered by the Non-RT-RIC 106 are composed of the rApp(s) 104. With the Non-RT-RIC 106, the rApp(s) 104 may be designed to provide granular service assurance and may improve the quality-of-experience wherever needed.
[0041] The Non-RT-RIC 106 is a logical function that enables non-real-time control and optimization of the ORAN elements and resources, AI/ML workflow including model training and updates, and policy-based guidance of applications/features in the Near-RT RIC 108 using the rApp(s) 104. The Non-RT-RIC 106 communicates to the Near-RT RIC using the A1 interface. The Non-RT-RIC 106 logically terminates the A1 interface.
[0042] The Near-RT-RIC 108 is a logical function that enables near-real-time control and optimization of the O-RAN elements and resources such as the E2 node 110 via fine-grained data collection and actions over E2 interface. The Near-RT-RIC 108 controls over the E2 node 110 using the policies and the enrichment data provided via A1 interface from the Non-RT-RIC 106.
[0043] Non-Real Time (Non-RT) control functionality (> 1s) and Near-Real Time (Near-RT) control functions (< 1s) are decoupled in an RIC (RAN Intelligent Controller). The Non-RT functions include service and policy management, RAN analytics and model-training for some of the near-RT RIC functionality, and non-RT RIC optimization.
[0044] The Near-RT-RIC 108 may host one or more xApps that use E2 interface to collect near real-time information and provide value added services. xAPP is an independent software plug-in to the Near-RT-RIC 108 to provide functional extensibility to the RAN by third parties. The Near-RT-RIC 108 can be provided different functionalities by using programmable modules as xAPPs, from different operators and vendors.
[0045] The Near-RT-RIC 108 connects to the E2 node 110 over E2 interface. The E2 node may be composed of an Open Central Unit (O-CU), an Open Distributed Unit (O-DU) and an Open Radio Unit (O-RU). The O-CU is a logical node hosting RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol) and PDCP (Packet Data Convergence Protocol). The O-CU may be a disaggregated O-CU and may include two sub-components: Open Central Unit Control Plane (O-CU-CP) and Open Central Unit User Plane (O-CU-UP). The O-CU-CP is a logical node hosting the RRC and the control plane part of the PDCP. The O-CU-CP supports O1, E2, F1-c, E1, X2-c, Xn-c and NG-c interfaces for interaction with other components/entities. Similarly, the O-CU-UP is a logical node hosting the user plane part of the PDCP and the SDAP and uses O1, E1, E2, F1-u, X2-u, NG-u and Xn-u interfaces.
[0046] The O-DU is a logical node hosting RLC/MAC (Medium access control)/High-PHY layers based on a lower layer functional split and supports O1, E2, F1-c, F1-u, OFH CUS–Plane and OFH M-Plane interfaces.
[0047] The O-RU is a logical node hosting Low-PHY layer and RF (Radio Frequency) processing based on a lower layer functional split. This is similar to 3GPP’s “TRP (Transmission And Reception Point)” or “RRH (Remote Radio Head)” but more specific in including the Low-PHY layer (FFT/iFFT, PRACH (Physical Random Access Channel) extraction). The O-RU utilizes OFH CUS–Plane and OFH M-Plane interfaces.
[0048] The O-Cloud 112 is a collection of physical RAN nodes (that host various RICs, CUs, and DUs), software components (such as operating systems and runtime environments) and the SMO 102, where the SMO manages and orchestrates the O-Cloud 112 from within via O2 interface.
[0049] Now referring to the various interfaces used in the ORAN 100 as mentioned above.
[0050] The O1 interface is element operations and management interface between management entities in the SMO 102 and O-RAN managed elements, for operation and management, by which FCAPS (fault, configuration, accounting, performance, security) management, Software management, File management shall be achieved. The O-RAN managed elements include the Near RT-RIC 108 and the E2 node 110. The management and orchestration functions are received by the aforesaid O-RAN managed elements via the O1 interface. The SMO 102 in turn receives data from the O-RAN managed elements via the O1 interface for AI (artificial intelligence) model training.
[0051] The O2 interface is a cloud management interface, where the SMO 102 communicates with the O-Cloud 112 it resides in. Typically, operators that are connected to the O-Cloud 112 can then operate and maintain the O-RAN 100 with the O1 or O2 interfaces.
[0052] The A1 interface enables communication between the Non-RT-RIC 106 and the Near-RT-RIC 108 and supports policy management, machine learning and enrichment information transfer to assist and train AI and machine learning in the Near-RT-RIC 108. Additionally, the R1 interface, which is an internal interface to the SMO 102, through which the rApp(s) 104 leverages the functionality exposed to further provide value added services for ORAN operation, such as driving the A1 interface, generating the enrichment information for the use of other rApp(s), recommending set of actions that may be applied over the O1/O2 interface. Further, the R1 interface supports easy onboarding of the rAPP(s) 104.
[0053] The Near-RT-RIC 108 connects to the E2 node 110 via the E2 interface for data collection. The E2 node can connect only to one Near-RT-RIC, but one Near-RT-RIC can connect to multiple E2 nodes. Typically, protocols that go over the E2 interface are control plane protocols that control and optimize the elements of the E2 node and the resources they use.
[0054] FIG. 2 is a sequence diagram 200 for optimizing Physical Cell ID (PCI) assignment in the O-RAN 100. It may be noted that in order to explain the sequence steps of the sequence diagram 200, references will be made to the elements explained in FIG. 1.
[0055] Initially, an optimization service for PCI is deployed in the rApp 104 and the rApp 104 with the optimization service (or PCI optimization service) is registered with the Non-RT-RIC 106 and thus with the SMO 102. The rApp 104 is in connection with the Non-RT-RIC 106 using an interface such as the R1 interface. The rApp 104 consumes network data having CM notification of new cell deployment or cell(s) with neighbour relation change, FM about PCI conflict(s) and PM and determines a PCI for newly deployed cell or for the cell(s) whose neighbour relation has been changed or determines PCI changes to resolve flagged PCI conflicts. Further, the O1 interface is used for the O-RAN 100 to get data updates, fault supervision and network configuration, wherein the O1 interface links the SMO 102 to an E2 node 110 either directly or via an O1 interface adapter, where the E2 node creates a measurement job and the SMO 102 subscribes to at least one of a Fault Management (FM), a Configuration Management (CM), a Performance Management (PM) data from the E2 node. The E2 node 110 comprises the O-DU and the O-CU and executes configuration and sends CM change confirmation to the rApp 104. These and other details are explained below.
[0056] At step 1, the rApp 104 sends a subscription request for subscribing to data such as Fault Management (FM)/Configuration Management (CM)/Performance management (PM)) data from the Non-RT-RIC 106 via the R1 interface. The Non-RT-RIC 106 transmits the subscription request to the SMO 102 at step 2 via internal interface(s) and the SMO 102, in turn, sends the same to the involved E2 node 110 via the O1 interface at step 3. At step 3, along with subscription request, the SMO 102 also transmits a request for creating Managed Object Instance (MOI) to the E2 node 110. Here, the E2 node 110 comprises the O-CU/O-DU (already detailed above).
[0057] The E2 node (O-CU/O-DU), at step 4, creates the MOI, measurement job and handles the subscription request and sends a (subscription) response to the SMO 102 via the O1 interface at step 5. The SMO 102 further instructs a database 114 to update the subscription response at step 6, and simultaneously transmits the subscription response to the Non-RT-RIC 106 using the O1 interface at step 7 that is finally sent to the rApp 104 at step 8.
[0058] As a new cell is created or neighbour relation of the cell(s) is changed, the SMO 102 signals CM notification to the Non-RT-RIC 106 at step 9 and the Non-RT-RIC 106 relays the CM notification regarding new cell creation or neighbour relation change to the rApp 104 at step 10.
[0059] At step 11, the rApp 104 sends query to retrieve data such as PCI configuration, or any other restriction from the database 114 via the Non-RT-RIC 106 (step 12). In response, the database 114 transmits network inventory and the PCI configuration to the rApp 104 at step 14 via the Non-RT-RIC 106 (step 13).
[0060] After receiving the data related to the network inventory and the PCI configuration, the rApp 104 initiates PCI optimization and PCI assignment (nRPCI) at step 15. The process of PCI assignment is discussed below.
[0061] Once PCI optimization has been performed, the rApp 104 sends notification to the Non-RT-RIC 106 indicating the PCI changes/assignment to the cell(s) (nRPCIs) and nRTCI changes/assignment to all neighbour cells of each cell with nRPCI change at step 16, that is further transmitted to SMO 102 at step 17.
[0062] At step 18, the SMO 102 sends the CM message to the E2 node(s) 110 of the new cell (nRPCI) or of the cell(s) with neighbour relation change. At step 19, the E2 node 110 transmits FM in case of PCI conflict (due to just or previously assigned PCI). The FM with PCI conflict is notified to the Non-RT-RIC 106 by the SMO 102 at step 20 and further notified to the rApp 104 by the Non-RT-RIC 106 at step 21.
[0063] At step 22, the rApp 104 sends query to retrieve data such as PCI configuration, or any other restriction from the database 114 via the Non-RT-RIC 106 (step 23). In response, the database 114 transmits network inventory and the PCI configuration to the rApp 104 at step 25 via the Non-RT-RIC 106 (step 24).
[0064] At step 26, the rApp 104 performs PCI assignment optimization and PCI change (nRPCI changes) operations and at step 27, the rApp 104 transmits the PCI change to cells (nRPCIs) and nRTCI changes to all neighbour cells of each cell with nRPCI change to the Non-RT-RIC 106 that is further notified to the SMO 102 at step 28. Thereafter, the SMO 102, at step 29 through the O1 interface, sends CM message with nRPCI and nRTCI changes to the involved E2 node(s) 110. In response, the E2 node 110 shares CM status with the SMO 102 at step 30 via the O1 interface.
[0065] The CM status is further transmitted to the Non-RT-RIC 106 from the SMO 102 at step 31 and to the rApp 104 from the Non-RT-RIC 106 at step 32.
[0066] Lastly, the rApp 104 sends the updated configuration to the database 114 via the Non-RT-RIC 106 at step 33 and step 34. Accordingly, the database 114 stores the updated configuration of the cells.
[0067] Now referring to the PCI assignment and reassignment techniques (method) 200a for PCI (re-)assignment optimization mentioned in the above steps (shown in FIG. 2a). The PCI (re-)assignment optimization is done by implementing the PCI assignment and reassignment techniques in the rApp in the Non-RT-RIC/SMO. The optimal PCI assignment occurs both at the time of a cell activation or cell topology/configuration change and upon receiving the FM due to the PCI collision and/or PCI confusion. The technique of PCI assignment and reassignment is executed by the rApp 104 hosted by the Non-RT-RIC 106 in the O-RAN 100. The PCI assignment and reassignment techniques may be implemented using complete (re-)assignment and/or fault management induced local re-assignment.
[0068] The PCI (re-)assignment technique may take one or more inputs such as the FM 202, cell addition (single or multiple) 204 or any other neighbour relations. Based on the FM 202 input, a cluster K around a cell causing the FM is identified at 210. Similarly, on the basis of cell addition (single or multiple) 204 input, the cluster K is set around the cell being added at 212. Simultaneously, cluster K = O (Set of all cells) is set at 208 if any full PCI (re-)assignment 206 has been performed previously. Based on the cluster K = O, unique PCIs are assigned to first M cells from the cluster K and X = M is set at 214, where X = # of unique PCIs assigned and M = # of “seed” cells (parameter). Later, next random cell for PCI assignment from the cluster K is considered at 216, based on the identified cluster K around the cell causing the FM 210, set cluster K around the cell being added 212 and assigned unique PCIs and X=M 214, for which n = 0 and N = ceiling(a*X) are set at 218, where n = Counter, N = Number of PCI reuse attempts and a = PCI reuse fraction (parameter). The counter n is increased and a PCI already used (without resampling) is randomly picked at 220. The PCI (re-)assignment technique further determines whether there is a PCI conflict at 224.
[0069] In case of the PCI conflict, the PCI (re-)assignment technique determines whether n = N at 222. If n = N, then a new unique PCI is assigned and X is updated at 230. Further, the PCI (re-)assignment technique determines at 232 if there are more cells for PCI assignment. If yes, the PCI (re-)assignment technique returns to step 216 for PCI assignment. The loop will be continued till there is no cell left for PCI assignment. On the other hand, if there are no further cells for PCI assignment, the PCI (re-)assignment technique ends at 234. If N = n, then the PCI (re-)assignment technique returns to step 220.
[0070] Similarly, in case if there is no PCI conflict, the PCI (re-)assignment technique determines at 226 if there are more cells for PCI assignment. If yes, the PCI (re-)assignment technique returns to step 216 for PCI assignment. The loop will be continued till there is no cell left for PCI assignment. On the other hand, if there are no further cells for PCI assignment, the PCI (re-)assignment technique ends at 228.
[0071] Conclusively, the PCI (re-)assignment technique iteratively assigns PCIs to the next neighbour-set such that a) specified constraints (related to collision, confusion and modulo 3/30 non-overlap between neighbours, possibly minimum PCI-reuse distance, etc.) are satisfied, b) consider one cell at a time and first try to reuse the PCIs already used and then assigning PCI from equally likely set of the PCIs already used and checking if the constraints are satisfied and repeating the above (without replacement) for at most N (e.g., = aX, where a is a specified parameter in an interval (0, 1)) until the constraints are satisfied. If the constraints are not satisfied after N attempts, the complete (re-) assignment method includes using a new unique PCI and updating X. When a PCI is assigned to each cell without using more than maximum number of unique PCIs available, the procedure has concluded successfully.
[0072] Advantageously, the PCI (re-)assignment technique of the present disclosure is scalable and optimizes publicly available and/or published algorithms. Further, the PCI (re-)assignment technique of the present disclosure avoids getting trapped in local minima and is robust, e.g., the FM is resolvable with a minimum number of PCI changes. Furthermore, the present disclosure enables using O1 interface or O1-equivalent interface for the O-RAN or Non-O-RAN respectively to get data updates for network configuration without using the Near-RT-RIC 108.
[0073] FIG. 3 illustrates various hardware components/elements of the rApp 104 for optimizing the PCI assignment. It may be noted that in order to explain FIG. 3, references will be made to the elements and steps explained in FIG. 1 and FIG. 2.
[0074] Referring to FIG. 3, various hardware elements of the rApp 104 may be a PCI optimizer 302, at least one processor and/or controller 304, a connector 306 and a storage unit 308. However, the components of the rApp 104 are not limited to the above-described example, and for example, the rApp 104 may include more or fewer components than the illustrated components. In addition, the PCI optimizer 302, the controller 304, the connector 306 and the storage unit 308 may be implemented in the form of a single chip.
[0075] The PCI optimizer 302 may deploy the optimization service in the rApp 104 and may register the optimization service as a PCI-rApp within the SMO 102, wherein the rApp 104 is in connection with the Non-RT-RIC 106 through the interface, such as R1 interface.
[0076] Thereafter, the PCI optimizer 302 utilizes the complete (re-) assignment and/or the fault management induced local re-assignment techniques as explained above. That is, the PCI optimizer 302 may assign a listing of unique predefined PCIs (Physical Cell IDs) to operating cells (interchangeably referred as cells, a plurality of cells or a plurality of operating cells) of a selected range after satisfying one or more constraints. The operating cells have neighbour relations, i.e., for a particular operating cell, a set of operating cells are its neighbours. The PCI optimizer 302 may assign or conclude a successful status of the procedure, if the assignment of PCI to each operating cell completes without using more than the listing of unique predefined PCIs.
[0077] If any fault is detected or notified from any of the selected range, the PCI optimizer 302 identifies a cluster of operating cells around an operating cell generating a fault message and re-assigns the listing of unique predefined PCIs to the cluster of operating cells, representing a faulty cluster, based on the one or more constraints. The one or more constraints may also be termed as predefined or specified constraints. The or more constraints may be collision, confusion, and modulo 3/30 non-overlap between neighbours, and possibly minimum PCI-reuse distance, for example.
[0078] Additionally, the PCI optimizer 306 performs all the tasks of the rApp 104 as explained in FIG. 2. Some of the example tasks are that the rApp 104 consumes network data (CM notification of new cell deployment or neighbour relation change, FM about PCI conflict(s) and PM) and also determines the PCI for newly deployed cell or PCI changes to resolve flagged PCI conflicts.
[0079] The controller 304 may control a series of processes so that the rApp 104 can operate according to description described above. For example, the controller 304 may transmit/receive the information through the connector 306. There may be a plurality of controllers 304, and the controller 304 may perform a component control operation of the rApp 104 by executing a program stored in the storage unit 308.
[0080] The storage unit 308 may store programs and data necessary for the operation of the rApp 104. The storage unit 308 may be composed of a storage medium such as read only memory (ROM), random access memory (RAM), hard disk, compact disc ROM (CD-ROM), and digital versatile disc (DVD), or a combination of storage media. Also, there may be a plurality of storage units 308. In an implementation, the storage unit 308 may include the database 114.
[0081] The connector 306 may be a device that connects the rApp 104 with other elements/components and may perform message transmission and reception.
[0082] FIG. 4 is a flowchart 400 illustrating a method for optimizing the PCI assignment. It may be noted that in order to explain the method steps of the flowchart 400, references will be made to the elements explained in FIG. 1 through FIG. 3.
[0083] At step 402, the method includes deploying the optimization service in the rApp 104 and registering the optimization service as the PCI-rApp within the SMO 102, wherein the rApp 104 is in connection with the Non-RT-RIC 106 through the interface, such as R1 interface.
[0084] At step 404, the method includes assigning the listing of unique predefined PCIs (Physical Cell IDs) to the operating cells of the selected range after satisfying the one or more constraints. The operating cells have neighbour relations, i.e., for a particular operating cell, a set of operating cells are its neighbours.
[0085] At step 406, the method indicates that the procedure has been concluded successful if the assignment of the PCI to each operating cell completes without using more than the listing of unique predefined PCIs.
[0086] It may be noted that the flowchart 400 is explained to have above stated process steps; however, those skilled in the art would appreciate that the flowchart 400 may have more/less number of process steps which may enable all the above stated implementations of the present disclosure.
[0087] The various actions, acts, blocks, steps, or the like in the flow chart and sequence diagrams may be performed in the order presented, in a different order or simultaneously. Further, in some implementations, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the present disclosure.
[0088] The embodiments disclosed herein can be implemented using at least one software program running on at least one hardware device and performing network management functions to control the elements.
[0089] It will be apparent to those skilled in the art that other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above-described embodiment, method, and examples, but by all embodiments and methods within the scope of the invention. It is intended that the specification and examples be considered as exemplary, with the true scope of the invention being indicated by the claims.
[0090] The methods and processes described herein may have fewer or additional steps or states and the steps or states may be performed in a different order. Not all steps or states need to be reached. The methods and processes described herein may be embodied in, and fully or partially automated via, software code modules executed by one or more general purpose computers. The code modules may be stored in any type of computer-readable medium or other computer storage device. Some or all of the methods may alternatively be embodied in whole or in part in specialized computer hardware.
[0091] The results of the disclosed methods may be stored in any type of computer data repository, such as relational databases and flat file systems that use volatile and/or non-volatile memory (e.g., magnetic disk storage, optical storage, EEPROM and/or solid-state RAM).
[0092] The various illustrative logical blocks, modules, routines, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. The described functionality can be implemented in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosure.
[0093] Moreover, the various illustrative logical blocks and modules described in connection with the embodiments disclosed herein can be implemented or performed by a machine, such as a general purpose processor device, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. A general-purpose processor device can be a microprocessor, but in the alternative, the processor device can be a controller, microcontroller, or state machine, combinations of the same, or the like. A processor device can include electrical circuitry configured to process computer-executable instructions. In another embodiment, a processor device includes an FPGA or other programmable device that performs logic operations without processing computer-executable instructions. A processor device can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor device may also include primarily analog components. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few.
[0094] The elements of a method, process, routine, or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor device, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of a non-transitory computer-readable storage medium. An exemplary storage medium can be coupled to the processor device such that the processor device can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor device. The processor device and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In the alternative, the processor device and the storage medium can reside as discrete components in a user terminal.
[0095] Conditional language used herein, such as, among others, "can," "may," "might," "may," “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain alternatives include, while other alternatives do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more alternatives or that one or more alternatives necessarily include logic for deciding, with or without other input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular alternative. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.
[0096] Disjunctive language such as the phrase “at least one of X, Y, Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain alternatives require at least one of X, at least one of Y, or at least one of Z to each be present.
[0097] While the detailed description has shown, described, and pointed out novel features as applied to various alternatives, it can be understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the scope of the disclosure. As can be recognized, certain alternatives described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others.