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5G Glossary of Terms

Reference Guide Glossary of Terms Reference Guide

Numerics AF (Application Function) An element offering applications that require dynamic policy and/or charging control over the IP First generation of mobile network technology, offering Connectivity (IP-CAN) user-plane behavior. analog-based voice services. The AF communicates with the Policy and Charging Rules Second generation of mobile network technology, offering Function (PCRF) to transfer dynamic session information, digital voice and low-speed data services. required for PCRF decisions, as well as receive IP-CAN specific Third generation of technology, offering information and notifications about IP-CAN bearer-level events. broadband data services. One example of an AF is the Proxy-Call Session Control Function (P-CSCF) of the IP Multimedia Core Network Subsystem (IMS). Fourth generation of cellular network technology, offering high-definition digital voice and improved data performance AMF (Access and Function) over 3G. Provides (UE) authentication, authorization, registration, reachability, mobility management, and connection 5G Fifth generation of cellular network technology offering management functions. UE using multiple access technologies greatly improved performance gains over 4G related to access could be connected to a single Access and Mobility speed, latency, number of connected devices, coverage, Management Function (AMF) because the AMF is independent availability, energy consumption, and guaranteed end-to-end of the access technologies. performance via Network Slicing. AN (Access Network) One of three major components of 5G NR (New ) The 3rd Generation Partnership Project’s a 5G system, defining all equipment within the access part (3GPP) fifth-generation radio standard that leverages millimeter of the 5G network infrastructure. waves, enhanced small cells, Massive-Input Massive-Output (MIMO), beamforming, licensed/unlicensed spectrum, and AUSF (Authentication Server Function) Stores data for full-duplex technologies. authentication of UE used during the UE attachment sequence. For 5G, basic security mechanisms for 4G could be reused. 3GPP (3rd Generation Partnership Project) A group of seven However, as 5G enables new service and business models that standard development organizations (ARIB, will require many different security applications, AUSF will allow ATIS, CCSA, ETSI, TSDSI, TTA, TTC), known as Organizational UE authentication using these different security applications in Partners; provides its members with a stable environment this new framework. to produce reports and specifications that define cellular telecommunications network technologies, including radio access, the core transport network, and service capabilities. B Backhaul The transport network connecting the Radio Access A Network (RAN) to the mobile core network. In a Distributed RAN (D-RAN) architecture, it connects the to the core. In a AAS (Active Antenna System) A 3GPP-specified system Centralized-RAN (C-RAN) architecture, it connects the physical that combines an antenna array with an active transceiver or virtual centralized/cloud 4G/5G Baseband Units (BBUs) to the unit array and a radio distribution network unit. 4G/5G core.

2 BBU (Baseband Unit) A unit of the telecom systems that CU (Centralized Unit) A logical node hosting Radio Resource processes baseband signals and can be deployed in a Control (RRC), Service Data Adaptation Protocol (SDAP), and distributed (D-RAN) or centralized/cloud (C-RAN) manner. Packet Data Convergence Protocol (PDCP) sublayers of the gNB or Beamforming Uses multiple antennas to control the direction ng-eNB, or RRC and PDCP sublayers of the en-gNB. It centralizes of a wavefront by appropriately weighting magnitude and phase and controls the operation of one or more gNB-DUs, ng-eNB-DUs of individual antenna signals, providing better coverage to or en-gNB-DUs. The CU terminates the fronthaul Higher Layer specific areas along edges of cells. Beamforming algorithms Split (HLS) interface connected with the Distributed Units (DUs). can be used to reduce transmission interference from CUPS (Control and User Plane Split) Refers to the separation Multiple–Input Multiple-Output (MIMO) antennas by providing of the control and user plane functions of an LTE EPC packet- the precisely coordinated pattern through the air to each user, forwarding elements. These elements are the Serving Gateway allowing the exchange of more data for multiple users at once. (S-GW), the Packet Data Network (PDN), Packet Gateway (P-GW), and the Traffic Detection Function (TDF). With CUPS, a new C control signal is also being defined between the control plane part and the user plane part of the split elements; this control Carrier Aggregation Technique combining two or more signal is primarily used for session management purposes. channels (carriers), contiguous or not, to deliver a higher aggregate data rate to subscribers. D CORD (Central Office Rearchitected as a Data Center) Transforms traditional central offices using data center DensificationRefers to increasing the number of cell sites on technology for the purpose of virtualizing traditional telecoms the network for improved coverage and capacity. network elements into a more virtualized construct. DN (Data Network) The network hosting operator data-centric CN (Core Network) One of three major components of the services, internet, or third-party data-centric services. 3GPP system defining all equipment within the core segment D-RAN (Distributed ) A traditional RAN of the mobile network. architecture where a standalone base station has both the BBU CoMP (Coordinated Multi-Point) A set of techniques to and the Radio Unit (RU) installed at a cell site. Also, base stations improve mobile networks’ reliability and performance, with a D-RAN architecture are generally installed inside of a medium particularly at the cell edges, enhancing the signal and reducing or large building for stable power supply and air conditioning needs. interference. CoMP allows terminals to connect simultaneously The D-RAN base station will have a backhaul interface into the to multiple adjacent base stations, which can coordinate core switching center, terminating to circuit-switching and/or downlink and uplink transmission. packet-switching core network systems accordingly. Control Plane The signaling function of a 3GPP system largely DSS (Dynamic Spectrum Sharing) Technique that allows dealing with non-packet forwarding functions including mobility 5G NR and 4G to share the same spectrum to introduce management, connection establishment, and Quality of Service 5G NR over an existing 4G footprint by leveraging low-band or (QoS) control. With Rel-14 and Rel-15, 3GPP aims to separate mid-band spectrum already in use to extend coverage of new the user plane and control plane functions respectively for the 5G services without disrupting active 4G services. Evolved Packet Core (EPC) in 4G/Long-Term Evolution (LTE) DU (Distributed Unit) A logical node hosting Radio Link and the Next Generation Core (NGC) in 5G. Control (RLC), Media Access Control (MAC), and Physical (PHY) CPRI (Common Public Radio Interface) Digitized and serial sublayers of the gNB, en-gNB, or ng-eNB. Its operation is partly internal radio base station interface that establishes a connection controlled by the Centralized Unit (CU). One DU supports one between Radio Equipment Controller (REC), commonly known as or multiple cells. One cell is supported by only one DU. The DU BBU, to the Radio Equipment (RE), commonly known as Remote terminates the fronthaul HLS interface connected with the CU. Radio Heads (RRH), via single-hop and multi-hop topologies. E C-RAN (Centralized/Cloud-Radio Access Network) Centralization and virtualization of 4G BBU or 5G Centralized eCPRI (Enhanced Common Public Radio Interface) Unit (CU) processing, which improves cell coordination, The specification of an internal radio base station interface scheduling, resource pooling, and load balancing. establishing a connection between eCPRI Radio Equipment Controller (eREC) and eCPRI Radio Equipment (eRE) via a packet- C-RAN Hubs To implement a centralized RAN or cloud based transport network. Three different information flows are (virtualized) RAN architecture, BBUs and CUs need to be being defined in this specification including eCPRI User Plane pooled together in regional locations called C-RAN hubs (or, data, Control and Management Plane data, and Synchronization. alternatively, base station hotels or BBU/CU pools/hotels).

3 Edge Cloud A trending IT and network architecture in which FWA (Fixed Wireless Access) Encompasses any wireless the cloud (virtual compute and storage resources) is scattered system that connects to a fixed location, such as a household across multiple sites closer to the edge of the network, where or an office. There is no cable, the (connection between content is both created and consumed, to meet the expected the user and the network) is delivered through a radio. In the Quality of Experience (QoE) of a new generation of cloud-native context of 5G and mobile networks, FWA refers to the possibility applications that are compute-intensive and latency-sensitive. of leveraging the mobile network infrastructure to offer fixed Traditional centralized cloud architectures will not meet QoE broadband services, as an alternative to wired infrastructure expectations for these applications and will require a more such as (DSL), cable, or fiber. dynamic and distributed cloud model. These applications can be both end-user focused or network driven (such as those G enabling C-RAN virtualization at hub sites). gNB (gNodeB) A node providing New Radio (NR) user plane and Evolved Packet Core (EPC) The core network of the control plane protocol terminations towards the UE, connected 4G LTE system. via the Next Generation (NG) interface to the 5G Core (5GC). eMBB (Enhanced ) The initial and most widespread use case for 5G and one of the three essential H 5G use cases. It refers to the improvement in the mobile Hard Slicing Hard Network Slicing allocates network resources broadband experience that 5G is expected to provide over to different services (network slices) in a way that fully isolates previous mobile standards and technologies, increasing peak one service from the other. The slices can be designed to and average data rates up to over ten times. deliver specified and individual guaranteed performance levels. en-gNB A node providing 5G NR user plane and control plane Hard slicing can be implemented through Optical Transport protocol terminations towards the UE, acting as secondary Network (OTN) and Dense Wavelength Division Multiplexing node in Evolved-Universal Terrestrial Radio Access-New (DWDM) or, more efficiently to 5G applications, through FlexE. Radio (EN-DC). EN-DC E-UTRA (LTE) to 5G NR Dual Connectivity. An I architecture where both LTE eNodeB and NR gNB will be IMT-Advanced (International Mobile Telecommunications- co-deployed, allowing the UE to simultaneously establish Advanced) Represents a secure all-IP mobile broadband two radio bearers, each to the respective NodeBs. system for wireless devices, going beyond mobile phones systems marketed as 3G; referenced as 4G or 4.5G. F IMT-2020 (International Mobile Telecommunications-2020) FlexE (Flexible Ethernet) A standard defined by the Optical A program led by Working Party 5D of ITU’s Radio Internetworking Forum (OIF) for extending Ethernet PHYs to Communication Sector (ITU-R) to develop “IMT for 2020 and support bonding, sub-rating, and channelization while also Beyond,” setting the stage for 5G research activities around enabling channel management and time synchronization. FlexE the world. The detailed investigation of the key elements of is a key technology to allow effective service isolation over a 5G are being realized through successful partnerships between shared infrastructure, implementing hard Network Slicing. ITU-R and the mobile broadband industry, as well as with key stakeholders in the 5G community. Fronthaul Defines the network segment connecting RUs to physical or virtual DUs in a C-RAN architecture. Fronthaul is IoT (Internet of Things) System of connected devices, further sub-categorized as fronthaul Higher Layer Split (HLS) machines, objects, or any living or non-living thing equipped and fronthaul Lower Layer Split (LLS). with unique identifiers and the ability to transmit data over a network without necessary human intervention. It is Fronthaul HLS (Higher Layer Split) Defines the open the ubiquitous evolution of Machine-to-Machine (M2M), interconnection of a gNB-CU or ng-eNB-CU to a gNB-DU or encompassing the phenomenon of increasingly connecting ng-eNB-DU respectively, allowing the CUs or DUs to be sensors and machines in networks, whether to gather data, supplied by different manufacturers. A fronthaul HLS interface leverage centralized computing capabilities, or add intelligence will have both the control plane part and the user plane part. to machine decision and interaction between machines. 3GPP F1 interface is an example of a fronthaul HLS interface. IP (Internet Protocol) Internet communications protocol Fronthaul LLS (Lower Layer Split) Defines the interconnection suite for relaying data across network boundaries to enable of a DU with that of a RU. Common CPRI and eCPRI are both internetworking; essentially establishes the internet. examples of a fronthaul LLS. Specific to the eCPRI specification, the DU is being referred to as eREC, while the RU is being referred to as eRE.

4 L MIMO (Multiple-Input Multiple-Output) Allows sending and receiving of more than one data signal on the same channel at Latency Network latency is the time it takes for packets to the same time by using more than one antenna, thus improving travel through a network segment. the data rates between the transmitter and the receiver. Low Band The lower part of the electromagnetic spectrum mmWave (Millimeter Wave) A high-frequency wave wedged used by cellular communications, generally comprising between microwaves and infrared waves, in the millimeter band; frequencies below 1GHz. These lower-frequency bands have considered to deliver faster, higher-capacity 5G services. been the most used to power 3G and 4G networks, and provide broader coverage, as they travel across great distances MNO (Mobile Network Operator) Provides wireless service(s) (lower free-space attenuation) and penetrate walls more easily. to wireless users by owning or leasing all components to sell On the other hand, lower frequencies imply lower bandwidth— and deliver wireless services over licensed wireless spectrum. a smaller capacity to carry data. MNOs include wireless service providers, wireless carriers, cellular companies, or mobile network carriers. LTE (Long-Term Evolution) A 4G mobile communications standard whereby users of the LTE network should see data MTC (Machine Type Communications) Communications speeds up to 10 times faster than 3G networks. between machines (things). LTE-A (Long-Term Evolution-Advanced) A mobile mMTC (Massive Machine-Type Communications) One of the communication standard that brings major enhancements three categories of 5G use cases, characterized by a large number to the LTE standard. Formally submitted to ITU-T in late of machines (things) within a specific area and communicating 2009 as a candidate 4G system meeting the requirements of with application servers residing in a core network. IMT-Advanced standard, LTE-A was standardized by 3GPP in M-CORD (Mobile-CORD) Focuses on a fully disaggregated March 2011 as 3GPP Release 10. and virtualized RAN and mobile core using open-source collaboration, bringing the value of data center economics M and cloud agility. M2M (Machine-to-Machine) Communications between machines, without human intervention. N MBH (Mobile Backhaul) The process of connecting cell sites NEF (Network Exposure Function) A network entity that (base stations) to network controller sites over wireline networks. exposes 3GPP core network capabilities to third parties, or non- Traffic engineering on such wireline networks is typically required 3GPP environments. NEF also provides security when services to enforce the necessary Quality of Service (QoS). or Application Functions (AFs access 5G Core nodes. It can be thought of as a proxy, or Application Programming Interface Massive MIMO (Multiple-Input Multiple-Output) Refers to the (API) aggregation point, or translator into the 5G Core Network. large number of antennas in the base-station antenna array that enables multiple spatially separated users to be catered to by Network Slicing Virtual slices of a physical network supporting the antenna array in the same time and frequency resource. specific performance guarantees. MEC (Multi-Access Edge Computing) Cloud computing at NG (Next Generation) Typically referring to the new 5G systems the edge of the network, performing necessary tasks closer to or specifications. the end-users. This environment is characterized by ultra-low NGC (Next Generation Core) Defines the mobile core elements latency and high bandwidth, as well as real-time access to radio of a 5G system. network information that can be leveraged by applications to ng-eNB A node providing E-UTRA (LTE) user plane and control improve the overall end-user experience, man or machine. plane protocol terminations toward the UE, connected via the Mid-Band The intermediate part of the electromagnetic NG interface to the 5GC. spectrum used by cellular communications, generally NR (New Radio) Commonly used term to reference 3GPP 5G comprising frequencies between 1GHz and 6GHz. Sitting in radio system. between the low band and millimeter wave spectrum, it offers a balanced compromise between coverage and bandwidth, and NSA (5G Non-Standalone Architecture) Early form of 5G is seen as a key band to provide broad coverage of 5G services. networks, where the network is supported by the existing 4G infrastructure. The control signaling is anchored to the 4G EPC. Midhaul Defines the network segment that, in a C-RAN architecture, connects the physical or virtual DU to the physical or virtual CU.

5 O RoE An IEEE standard (IEEE 1914.3) to encapsulate CPRI fronthaul traffic (originating from 4G radios) on a Time-Sensitive Open RAN A movement in the wireless industry that advocates Network (TSN) Ethernet connection and is a valuable tool to for hardware and disaggregation, openness, and facilitate the coexistence of 4G and 5G via integrated Ethernet- interoperability in RAN architectures, and acts towards the based fronthaul. standardization of open interfaces to allow multi-vendor RAN environments. Open RAN is also a RAN reference architecture RRH () A remote radio transceiver that that leverages industry-wide standards, defined by organizations connects to a radio base station unit via electrical or wireless such as the O-RAN Alliance, 3GPP, IEEE, and others, to support interface. The RRH is usually installed on a mast-top or the interoperability between different software and hardware tower-top location and is physically some distance away vendors. It is particularly important for C-RAN architectures, from the base station hardware, which is often in an indoor and heavily accelerated by RAN virtualization, given the rack-mounted location. disaggregation and multiplication of vendors that come with it. RU (Radio Unit) Converts radio signals from the antennas, O-RAN An acronym for Open RAN, but the hyphenated form where they are usually located, to digital signals that can be is mostly used to denote the O-RAN Alliance specifically, which transmitted over the fronthaul to a DU. was established in 2018 by a global consortium of network operators with the goal of promoting Open RAN standards S and driving its adoption. O-RAN is also used when referring to SA (5G Standalone Architecture) Full 5G, where the network standards defined by the alliance, such as in O-RAN 7-2x, which is independent of a 4G EPC, and the 5G NRs are connected indicates the open fronthaul standard for Split Option 7-2x. and controlled by a 5GC. O-RU / O-DU / O-CU An “O-” prefix usually qualifies a C-RAN Low-powered cellular radio access nodes that element (RU, DU, or CU) as O-RAN compliant, one that follows operate in licensed and unlicensed spectrum, serving fewer Open RAN standards. users at high access speeds over a small geographic area. SR (Segment Routing) An IP routing scheme that forwards P packets on the network based on a path dynamically PCF (Policy Control Function) A control plane function defined at the source node. Packet headers contain a list of responsible for policy control, and more specifically, managing segments—an ordered list of nodes—that provide instructions the QoS of individual service data flows in a 3GPP 5GC. PCF to be executed on subsequent network nodes. A key tool for enforces policies, usually based on usage volume reporting implementing soft Network Slicing, this routing framework from the User Plane Function (UPF). works over Multi-Protocol Label Switching (MPLS) or IP version PDN-GW or P-GW (Packet Data Network Gateway) Provides 6 (IPv6) networks. It allows network operators to dynamically access to packet data networks and is responsible for dictating adapt service-specific routing to avoid traffic congestion by QoS and bandwidth parameters in LTE, acts as IP router to steering packets over different paths based on service level mobile-specific tunneling and signaling protocols. This critical requirements and the current state of the network. function will be replaced with UPF in 5G. S-GW (Serving Gateway) The gateway that terminates the Private 5G A wireless enterprise-dedicated network built using interface toward Evolved UMTS Terrestrial Radio Access Network 5G cellular technology (such as 3GPP standards) rather than (E-UTRAN). S-GW is responsible for handovers with neighboring traditional wireless LAN technology (Wi-Fi). eNodeBs, as well as for data transfer of all packets across the user plane from the eNodeB to the P-GW. It is also the mobility anchor R point for Inter-Radio Access Technology (RAT) handover between different generations of mobile networks such as 2G/3G. RAN (Radio Access Network) A combination of wireless This critical function will be replaced with UPF in 5G. network elements and wireline network elements connecting end-users—man and machine—to the network core, delivering Soft Slicing A network prioritization scheme that dynamically specific services. The network elements present in this allocates resources to distinct services (slices). The network segment of the network include the base stations, base station slices are programmed to meet individual guaranteed service controllers, and mobile backhaul transmission equipment. levels. Network resources are not reserved as in the hard slicing. Soft Network Slicing is usually implemented using REC (Radio Equipment Controller) Virtual or physical element Segment Routing, controlled by an orchestration engine able that performs digital control of the radio system, handling to dynamically adjust network parameters to meet the required functions such as channel coding, , interleaving, service levels. and power control.

6 T V TSN (Time Sensitive Networking) IEEE 802.1 TSN is a collection V2X Vehicle-to-everything, or vehicle-to-anything, the exchange of specifications that enhance the functionalities of IEEE 802.1Q, of information between different vehicles, or between vehicles IEEE 802.1, and IEEE 802.3. These enhancements collectively and the roadway infrastructure, other devices, or the cloud. enable the creation of a Deterministic Ethernet switched network vDU / vCU / vBBU The “v” prefix qualifies the network element where fixed latency, low packet error loss rate, zero congestion, (DU, CU, or Baseband Unit) as virtualized, denoting that the and high availability network could be achieved. network functionality is implemented in software running on a generic hardware platform. U UDM (Unified Data Management)Where all subscriber data, X network service profiles, and network access policies are xHaul General term that encompasses fronthaul, midhaul, stored. The data in the UDM for specific subscribers could be and backhaul, but also the combination of all or some of accessed for verification of the subscriber during the initial these network segments. network attachment sequence of the subscriber. UE (User Equipment) One of three major components of a mobile network, defining all user devices connected to the network, man and machine. URLLC (Ultra-Reliable Low-Latency Communications) One of the three categories of 5G use cases, URLLC are high-performance network services designed to support critical applications that require fail-safe, real-time communications, and are highly sensitive to latency. These services will generally require a dedicated or isolated/prioritized infrastructure (likely leveraging Network Slicing) to assure the stringent service levels required. UPF (User Plane Function) A core network function, where service functions like packet routing and forwarding can be deployed in various locations or configurations. The UPF is the anchor point for any Intra-/Inter-RAT mobility. It also provides the Interface to a Visited Network UPF.

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