The document lists numerous abbreviations and acronyms related to telecommunications. It includes abbreviations for 3rd Generation Partnership Project (3GPP), Average Revenue Per User (ARPU), Evolved Packet Core (EPC), Global System for Mobile communications (GSM), Long Term Evolution (LTE), Mobile Switching Center (MSC), Policy and Charging Rule Function (PCRF), Public Land Mobile Network (PLMN), Session Initiation Protocol (SIP), and Virtual Network Function (VNF) among many others for technologies, standards, functions and components in telecommunications networks.

1. Abbreviations mentioned in the lecture
 3GPP - 3rd
Generation Partnership Project
 ARPU – Average Revenue Per User
 AS - Application Server
 AVP - Attribute Value Pairs
 AWS - Amazon Web Services
 CAPEX – Capital Expense
 CI - Continuous Integration
 EC2 - Elastic Compute Cloud
 EPC – Evolved Packet Core
 EPS - Evolved Packet System
 ETSI - European Telecommunications Standards Institute
 eUTRAN - evolved UMTS Terrestrial Radio Access Network
 FDM - Frequency Division Multiplex
 FDMA - Frequency Division Multiple Access
 GGSN - Gateway GPRS Support Node
 GMSC – Gateway MSC
 GPRS - General Packet Radio Service
 GSM - Global System for Mobile communications
 HLR - Home Location Register
 HSS - Home Subscriber Server
 IaaS – Infrastructure as a Service
 IMS – IP Multimedia Subsystem
 ISP – Internet Service Provider
 LTE- Long Term Evolution
 MANO – Management and Orchestration
 MIMO - Multiple Input Multiple Output
 MME - Mobility Management Entity
 MMTel - Multimedia Telephony
 MPLS - Multiprotocol Label Switching
 MSC - Mobile Switching Center
 NaaS – Network as a Service
 NFV – Network Function Virtualization
 OFDM - Orthogonal Frequency Division Multiplex
 OFDMA - Orthogonal Frequency Division Multiple Access
 OMA - Open Mobile Alliance
 OPEX - Operational Expense
 PaaS – Platform as a Service
 PCEF - Policy and Charging Enforcement Function
 PCRF - Policy and Charging Rule Function
 PLMN - Public Land Mobile Network
 POTS – Plain Old Telephone System
 PSTN – Public Switch Telephony Network
 QAM – Quadrature Amplitude Modulation
 RAN – Radio Access Network
 RCS - Rich Communications Suite

2.  RTP – Real-time Transport Protocol
 SaaS – Software as a Service
 SBC – Session Border Control
 SDP – Session Description Protocol
 SGSN – Serving GPRS Support Node
 SIP – Session Initiation Protocol
 SLA – Service Level Agreement
 SON – Self Organize Networks
 SRVCC - Single Radio Voice Call Continuity
 UA – User Agent
 UE – User Equipment
 UMTS - Universal Mobile Telecommunications Service
 VCC - Voice Call Continuity
 VLR – Visited Location Register
 VNF – Virtual Network Function
 WDM – Wavelength Division Multiplexing
Some more abbreviations related to telecom
 AAA - Authentication Authorization Accounting
 ACA - ACcounting Answer
 ACR - ACcounting Request
 AKA - Authentication and Key Agreement
 AoC - Advice of Charge
 ASA - Abort Session Answer
 ASR - Abort Session Request
 BBERF - Bearer Binding and Event Reporting Function
 BGCF - Breakout Gateway Control Function
 BTS - Base Transceiver Station
 CAMEL - Customised Application for Mobile network Enhanced Logic
 CAP - CAMEL Application Part
 CCA - Credit Control Answer
 CCF - Charging Collection Function
 CCR - Credit Control Request
 CPM – Converged IP Massaging
 CSCF - Call Session Control Function
 DRA - Diameter Routing Agent
 DTMF - Dual Tone Multiple Frequency
 EAB - Enhanced Address Book
 EDGE - Enhanced Data rates for GSM Evolution
 EIR – Equipment Identification Repository
 ENUM - E.164 Number Mapping
 GCID - GPRS Charging IDentifier
 GIBA - GPRS-IMS-Bundled Authentication
 GTA - Group Total Allowance
 IARI - IMS Application Reference ID
 IBCF - Interconnection Border Control Gateway

3.  ICID - IMS Charging IDentifier
 ICSI - IMS communication service IDentifier
 IETF - Internet Engineering Task Force
 IMAP - Internet Message Access Protocol
 IP-CAN - Internet Protocol Connectivity Access Network
 IP-SM-GW - IP short message gateway
 ISR - Idle state Signaling Reduction"
 ITU - International Telecommunication Union
 IWF – Interworking Working Framework
 LBS – Location Based Service
 MBMS - Multicast/Broadcast Multimedia Service
 MGCF - Media Gateway Control Function
 MMS - Multimedia Messaging Service
 MRFC - Multimedia Resource Function Controller
 MRFP - Multimedia Resource Function Processor
 MSISDN - Mobile Subscriber ISDN Number
 MSRP – Message Session Relay Protocol
 NAB - Network Address Book
 NAS – Non Access Stratum
 OAuth - open standard for authorization
 OCB - Outgoing Call Barring
 OCS - Online Charging System
 OFCS - Offline Charging System
 OIR - Originating Identification Restriction
 PCN - Packet Core network Node (SGSN, S–GW, P–GW)
 PDF - Policy Decision Function
 PDP - Packet Data Protocol
 PS – Presence Server
 PUID – Public User ID
 QoS – Quality of Service
 QCI – QoS Class Identifier
 RLS - Resource List Server
 RRC - Radio Resource Control
 SBCF - Session Based Charging Function
 SDF- Service Data Flow
 SGID - Subscriber Group ID
 SGML - Subscriber Group Member List
 SIMPLE - Session initiation protocol for Instant Messaging and Presence Leveraging
Extensions
 SPR - Subscription Profile Repository
 SSO – Single Sign On
 TDF - Traffic Detection Function
 TIP - Terminating Identification Presentation
 TISPAN - Telecommunication and Internet converged Services and Protocols for
Advanced Networking
 UDR - User Data Repository
 USIM - Universal Subscriber Identity Module
 XCAP - XML Configuration Access Protocol

4.  XDM – XML Document Management
 XML - Extensible Markup Language