I IFV I Information I Integer I interference IA Incoming Access IAB Integrated access backhaul IAB Interactive Advertising Bureau IAL inter-aerial links IAM Initial Address Message IANA Internet Assigned Number Authority IANA Internet Assigned Numbers Authority IARI IMS Application Reference Identifier IARP Inter-APN Routing Policies IARP Inter-APN Routing Policy IBB In-band blocking IBC Identity Based Cryptography IBCF Interconnect Border Control Function IBCF Interconnection Border Control Function IBCF Interconnection Border Control Functions IBE identity-based encryption IBE in-band emission IBS identity-based signatures IC Inactive Coding IC Interference Cancellation ICA Initiate Call Attempt ICB Incoming Call Baring ICB Incoming Call Barring ICB Incoming Communication Barring ICB Incoming Communications Barring ICCC IMS CS Control Channel ICCF IMS CS Control Function ICD Interface Control Document ICE Interactive Connectivity Establishment ICE ideal channel estimation ICF Identifier Caching Function ICF Identity Caching Function ICF Initial Connectivity Function ICI Incoming Call Information ICI Inter-Carrier Interference ICIC Inter-Cell Interference Cancellation ICIC Inter-Cell Interference Coordination ICLPR IN Calling Line presentation restriction ICM In Call Modification ICM Initial Codec Mode ICMP Internet Control Message Protocol ICN Information Centric Networks ICO Initial Connectivity Operator ICP Internet Code Point ICS IMS Centralized Services ICS Implementation Conformance Statement ICS In-channel selectivity ICSI IMS Communication Service Identification ICSI IMS Communication Service Identifier ICSI IMS-Communication-Service-Identifier ICV Integrity Check Value IDC In-Device Coexistence IDL Interface Definition Language IE Information Element IE Information Elements IEC Immediate Event Charging IEF Identity Event Function IEI Information Element Identifier IEI Information Element Identity IEM In-Ear-Monitoring IETF Internet Engineering Task Force IF intermediate frequency IFF Indirect far field IFPEI International Fixed Part Equipment Identity IFPSI International Fixed Part Subscription Identity IGF Intelligent Gap Filling IHOSS Internet Hosted Octet Stream Service IIN Issue Identification Number IK Integrity Key IL Insertion loss ILCM Incoming Leg Control Model ILP Inter-layer prediction ILPC Inner Loop Power Control IM IP Multimedia IM Identity management IM Information Model IM Instant Messaging IM Integrity Monitor IM Inventory Management IM interference mitigation IMBE Improved Multi-Band Excitation IMC IMS Media Coding IMC Internet Mail Consortium IMDN Instant Message Disposition Notification IMEI International Mobile Equipment Identities IMEI International Mobile Equipment Identity IMGCF Incoming Media Gateway Control Function IMRN IP Multimedia Routeing Number IMRN IP Multimedia Routing Number IMS IP Multimedia Subsystem IMS IP Multimedia Subsystems IMS IP Multimedia System IMS IP Multimedia subsystem IMS IP-Multimedia Subsystem IMS Identity Management Systems IMSI International Mobile Subscriber Identity IMT International Mobile Telecommunications IMU Inertial measurement unit IMUN International mobile user number IN Intelligent Network INAP Intelligent Network Application Protocol INE Interrogating Network Entity INIPUI IMS Network-Independent Public User Identities INIPUI IMS Network-Independent Public User Identity IOC Information Object Class IOC Information Object Classes IOCWI Inhibition Of Call Waiting Indication IODE Issue Of Data, Ephemeris IOI Inter Operator Identifier IOI Inter Operator Identifiers IOI Inter operator identifier IOV Input Offset Value IOV Input Offset Values IP Internet Protocol IPA IMMEDIATE PACKET ASSIGNMENT IPD Integrated Passive Device IPEG In-progress emergency group IPEPC In-progress emergency private call IPEPC In-progress emergency private communication IPTI Inter PDU Transmission Interval IQF Identifier Query Function IQF Identity Query Function IR Intermediate Rate IRG IMS Residential Gateway IRI Intercept Related Information IRIP Intended recipient identity presentation IRP Integration Reference Point IRP Integrations Reference Point IS Information Service IS Initialization Segment IS Initialization Segments IS Interference Suppression IS information Service ISCP Interference Signal Code Power ISD Initialization Segment Description ISD Inter Site Distance ISD Inter-site Distance ISDN Integrated Services Digital Network ISIM IM Subscriber Identity Module ISIM IMS Subscriber Identity Module ISIM Interference suppressing interference mitigation ISL Inter-Satellite Links ISMA Internet Streaming Media Alliance ISMP Inter-System Mobility Policy ISP Immittance spectral pairs ISPI Internetwork Service Profile Interrogation ISPM Internetwork Service Profile Modification ISPT Internetwork Service Profile Transfer ISRP Inter-System Routing Policy IST Immediate Service Termination IT Inactivity Test ITCC International telecommunication charge call ITCC International telecommunication charge card ITI Iu Timing Interval ITRP Information Time resource pattern ITS Intelligent Transport System ITS Intelligent Transport Systems ITS Intelligent transport system ITS intelligent transport systems ITU International Telecommunication Union IUA ICS User Agent IUT Implementation Under Test IUT Inter UE Transfer IUT Inter-UE Transfer IV Initialisation Vector IV Initialization Vector IVR Interactive Voice Response IVS In-Vehicle System