Open RAN

Acknowledgments xi 1 Introduction 1 Acronyms and Abbreviations 1 1.1 What is Open RAN 3 1.2 O-Ran Alliance 5 1.3 Open RAN Driving Forces 6 References 6 2 Open RAN Market Drivers 9 Acronyms and Abbreviations 9 2.1 Introduction 11 2.2 Reduction of RAN Total Cost of Ownership 11 2.2.1 The Role of Total Cost of Ownership 11 2.2.2 Entry of New Vendors 12 2.2.3 RAN Cloudification 13 2.2.4 RAN Programmability 13 2.3 O- RAN Network Optimization Enablers 14 2.4 Open RAN Challenges 15 2.4.1 Survey: The Biggest Barriers in Deploying Open RAN 15 2.4.2 Security in Open RAN 16 2.4.3 Vendor Interoperability, System Integration, and Maintenance 17 2.4.4 Cloud Native Implementation of CU and DU 18 References 19 3 Open RAN Stakeholders 21 Acronyms and Abbreviations 22 3.1 Introduction 22 3.2 Open RAN Operators 23 3.2.1 AT&T 23 3.2.2 Rakuten Mobile 23 3.2.3 Vodafone 24 3.2.4 1&1 Drillisch 25 3.2.5 MoU Group of Operators 25 3.2.6 DISH Wireless 26 3.2.7 Deutsche Telekom 27 3.2.8 Verizon 28 3.2.9 NTT DOCOMO 28 3.3 Open RAN Vendors 29 3.4 O-Ran Alliance 30 3.4.1 O-RAN ALLIANCE History 30 3.4.2 The Structure of O- RAN ALLIANCE 30 3.4.3 O-RAN Releases 32 3.4.4 O-RAN Certification and Badging Program 32 3.4.5 Open Testing and Integration Centers (OTICs) 34 3.4.6 O-RAN Software Community 35 3.4.7 PlugFests 36 3.5 Telecom Infrastructure Project (TIP) 37 3.6 ACCoRD Consortium 37 3.7 Open RAN Policy Coalition 38 3.8 Support from Governments 38 References 39 4 Open RAN Ecosystem Evolution 43 Acronyms and Abbreviations 43 4.1 Introduction 45 4.2 Technology 45 4.2.1 Standardization 45 4.2.1.1 O-RAN Specifications Releases 45 4.2.1.2 Open Fronthaul 48 4.2.1.3 O-Cloud 48 4.2.1.4 A1 and E2 Interfaces 49 4.2.2 Open RAN Products 49 4.2.2.1 Introduction 49 4.2.2.2 Ericsson 49 4.2.2.3 Nokia 50 4.2.2.4 Samsung 51 4.2.2.5 Rakuten 52 4.2.2.6 NEC 52 4.2.2.7 Fujitsu 53 4.2.2.8 Open RAN Software Vendors 53 4.2.2.9 Open RAN Chipset and Accelerator Vendors 54 4.2.3 Interoperability and Testing 55 4.3 Deployments 55 References 56 5 Open RAN Architecture 59 Acronyms and Abbreviations 59 5.1 O-RAN Logical Architecture 61 5.1.1 Additional RAN Split 63 5.1.2 RAN Programmability 64 5.1.3 Integrated Cloud Management 64 5.2 Service Management and Orchestration (SMO) 65 5.3 Non-RT RIC: Non- Real- Time RAN Intelligent Controller 65 5.4 Near-RT RIC: Near- Real- Time RAN Intelligent Controller 67 5.5 RAN Nodes and RAN Components 69 5.6 O-Cloud 69 5.7 Reference Points (Interfaces) 69 5.8 O-RAN High- Level Architecture 70 References 71 6 Non-Real-Time RAN Programming 73 Acronyms and Abbreviations 74 6.1 Introduction 75 6.2 SMO and Non-RT RIC in O-RAN Architecture 76 6.2.1 Service Management and Orchestration Framework (SMO) 76 6.2.2 Non-Real-Time Radio Intelligent Controller (Non- RT RIC) 77 6.2.3 rApps Hosted in Non- RT RIC; R1 Interface 77 6.3 A1 Interface 78 6.3.1 Introduction 78 6.3.2 Basics of A1 Interface REST Realization 79 6.3.3 A1 Policy Management Service (A1- P) 80 6.3.4 The Structure of A1 Policy 80 6.3.5 Policy Scope 83 6.3.6 Policy Objectives 84 6.3.7 Policy Resource Statement 85 6.3.8 Example of A1 Policy 87 6.3.9 A1 Policy Service Operations and Procedures 89 6.3.9.1 Introduction 89 6.3.9.2 Create Policy and Update Policy Operations 90 6.3.9.3 Query Policy Operation 92 6.3.9.4 Delete Policy Operation 93 6.3.9.5 Query Policy Status Operation 94 6.3.9.6 Notify Policy Status Change Operation 95 6.4 A1 Enrichment Information Service 96 6.4.1 Introduction 96 6.4.2 EI Job Creation 96 6.4.3 A1-EI Resource Identifiers and Operations 97 References 97 7 Real-Time RAN Programming 99 Acronyms and Abbreviations 100 7.1 Introduction 101 7.2 Near- RT RIC in the O-RAN Architecture 101 7.3 E2 General Aspects and Principles 103 7.4 RIC Functional Procedures 105 7.4.1 Introduction 105 7.4.2 RIC Subscription Procedure 107 7.4.2.1 Introduction 107 7.4.2.2 RIC Subscription Attributes 107 7.4.3 RIC Indication Procedure 109 7.4.4 RIC Control Procedure 110 7.4.5 RIC Query Procedure 111 7.5 E2 Services 112 7.5.1 Introduction 112 7.5.2 E2 Services Modeling Scheme 112 7.5.2.1 Selection of Formats and RAN Parameters 112 7.5.2.2 Selection of IE Formats and RAN Parameters for Event Trigger Definitions 115 7.5.3 Event Triggers 115 7.5.4 REPORT Service 117 7.5.4.1 Introduction 117 7.5.4.2 Reported Network Data Categories 117 7.5.4.3 REPORT Service Procedures 118 7.5.4.4 E2 Service Models for REPORT: E2SM-KPM and E2SM-RC 119 7.5.5 INSERT Service 121 7.5.5.1 Introduction 121 7.5.5.2 INSERT Service Procedures 122 7.5.5.3 E2SM-RC Service Model for INSERT 123 7.5.6 CONTROL Service 125 7.5.6.1 Introduction 125 7.5.6.2 E2 Service Models for CONTROL 126 7.5.7 POLICY Service 128 7.5.7.1 Introduction 128 7.5.7.2 POLICY Service Procedures 128 7.5.7.3 E2SM-RC (RAN Control) POLICY Model 129 7.5.7.4 Policy Approach “Control” Example 132 7.5.7.5 Policy Approach “Offset” Example 133 7.5.8 QUERY Service 134 7.6 Other E2 Service Models: E2SM-CCC 134 7.7 Example of CONNECTED State Mobility Solution with INSERT/CONTROL 135 7.8 Near-RT RIC Internal Architecture, xApps 136 7.8.1 Introduction 136 7.8.2 APIs for Support of xApps 138 References 139 8 RAN Decomposition and Cloudification 141 Acronyms and Abbreviations 142 8.1 Introduction 143 8.2 Open Fronthaul (OFH) Interface 145 8.2.1 Introduction 145 8.2.2 O-DU/O-RU Functional Split 145 8.2.3 Data Flow Over OFH Interface 146 8.2.4 OFH Protocol Architecture 147 8.2.4.1 Transport: eCPRI or RoE 147 8.2.4.2 C-Plane and U-Plane Application Layer 148 8.2.4.3 S-Plane 149 8.3 O-Cloud Platform 149 8.3.1 O-Cloud Architecture 149 8.3.2 Infrastructure Management Services 151 8.3.3 Deployment Management Services 152 8.4 Cloud Deployment Scenarios 153 8.4.1 Classification of Deployment Scenarios 153 8.4.2 Overview of Selected Deployment Scenarios 156 8.5 Hardware Acceleration 157 8.5.1 Introduction 157 8.5.2 Acceleration Abstraction Layer (AAL) 160 8.5.3 AAL Profile 160 8.5.4 AAL Interface API 162 8.5.4.1 Introduction 162 8.5.4.2 AALI-C-Mgmt: Common Administrative Operations/Actions/ Events 163 8.5.4.3 AALI-C-App: Common Operations/Actions/Events 166 References 167 9 Network Automation in O-RAN 169 Acronyms and Abbreviations 169 9.1 Introduction. SON Solutions Defined in 3GPP 171 9.2 Basics of Network Optimization in O-RAN 174 9.3 Traffic Steering Use Case 178 9.4 QoS-Based Resource Optimization Use Case 180 9.5 RAN Slice SLA Assurance Use Case 181 9.6 Context-based Dynamic Handover Management for V2X Use Case 183 9.7 QoE Optimization Use Case 184 9.8 NSSI Resource Optimization Use Case 185 References 187 10 O-RAN Management 189 Acronyms and Abbreviations 189 10.1 Introduction 190 10.2 O1 Interface 191 10.2.1 Introduction 191 10.2.2 OAM Architecture 191 10.2.3 Management Services in the O-RAN Architecture 193 10.2.3.1 Introduction 193 10.2.3.2 Provisioning Management Services 193 10.2.3.3 Fault Supervision Management Services 194 10.2.3.4 Performance Assurance Management Services 194 10.2.3.5 Trace Management Services 194 10.2.3.6 Other Management Services 195 10.2.4 Use Cases Supported in the O-RAN Operations and Maintenance Architecture 196 10.2.5 O-RAN Management Information Models 197 10.3 Open Fronthaul Management 198 10.3.1 M-Plane Architecture 198 10.3.2 M-Plane Functional Description 199 References 200 11 AI/ML Support in O-RAN Architecture 203 Acronyms and Abbreviations 203 11.1 Introduction 204 11.2 Control Loops 205 11.3 AI/ML Model Lifecycle 206 11.4 AI/ML Model Deployment Scenarios 207 11.5 Reinforcement Learning 209 11.6 Federated Learning 210 References 212 Index 213