t Control Channel Broadcast Channel Bearer Control Tunnelling Protocol Breakout Gateway Control Function Bearer Independent Call Control Buffer Status Report Base Station Sub-system Carrier Aggregation Camel Application Part Customized Alerting Tone Constrained Baseline Profile Component Carrier Credit-Control-Answer Completion of Communications to Busy Subscriber Common Control Channel Completion of Communications on Not Logged-in List of Abbreviations Completion of Communications on No Reply Credit-Control-Request Communication Deflection Charging Data Function Communication Diversion Charging Data Record Communication Forwarding on Busy User Control Format Indicator Communication Forwarding on Not Logged-in Communication Forwarding on no Reply Communication Forwarding Unconditional Charging Gateway Function Cipher Key Cancel-Location-Answer Cancel-Location-Request Call Management Commercial Mobile Alert System Comfort Noise Generation Cyclic Prefix Channel Quality Indicator Contention Resolution Identity C-RNTI Cell RNTI Customised Ringing Signal Circuit-Switched Call Session Control Function CS FallBack Charging Trigger Function Closed User Group Communication Waiting xviii VoLTE and ViLTE Dedicated Control Channel Downlink Control Information Delete-Subscriber-Data-Answer Delete-Subscriber-Data-Request DIAMETER Edge Agent DL-SCH Downlink Shared Channel Domain Name System Data Radio Bearer DM-RS Demodulation Reference Signal DIAMETER Routing Agent Discontinuous Reception DiffServ Code Point Dedicated Traffic Channel Discontinuous Transmission DwPTS Downlink Pilot Time Slot Emergency Access Transfer Function E-UTRAN Cell Global Identifier E-CSCF Emergency-CSCF Explicit Communication Transfer End Marker EPS Mobility Management evolved Node B Evolved Packet Core Evolved Packet System E-RAB EPS Radio Access Bearer List of Abbreviations EPS Session Management e-SRVCC enhanced Single Radio Voice Call Continuity Earthquake and Tsunami Warning System E-UTRAN Evolved Universal Terrestrial Radio Access Network Enhanced