io system architecture evolution service access point List of Abbreviations service based architecture service based interface secondary component carrier SCell secondary cell SC-FDMA single carrier-frequency division multiple access synchronization channel spatial channel model sub-carrier spacing slice differentiator service data adaptation protocol service data flow supplementary downlink spatial division multiple access service data unit security anchor functionality security edge protection proxy space-frequency block code SFI-RNTI slot format indication RNTI system frame number serving gateway system information system information block successive interference cancellation Single-input multiple-output signal to interference plus noise ratio SI-RNTI system information RNTI single-input single-output/soft-input soft-output service level agreement start and length indicator value security mode command session management function short message service short message service function sequence number signal to noise ratio S-NSSAI single network slice selection assistance information self-organizing network subscriber profile ID for RAT/frequency priority semi-persistent scheduling SPS C-RNTI semi-persistent scheduling C-RNTI scheduling request signaling radio bearer sounding reference signal synchronization signal SS/PBCH block SS-RSRP SS reference signal received power SS-RSRQ SS reference signal received quality secondary synchronization signal SS-SINR SS signal-to-noise and interference ratio slice/service type List of Abbreviations xxiii secondary timing advance group S-TMSI S-temporary mobile subscriber identity scheduling unit subscription concealed identifier supplementary uplink SU-MIMO single-user MIMO subscription permanent identifier tracking area timing advance transceiver array boundary tracking area code traffic aggregate description time alignment error timing advance group tracking area identity tracking area update transport block transmission configuration indicator transmission control protocol 