Section: 5.4.5a Data Volume and Power Headroom Reporting
Content: The Data Volume and Power Headroom reporting procedure is only applicable for NB-IoT UEs and is used to provide the serving eNB with information about the amount of data available for transmission in the UL buffers associated with the MAC entity, and to provide the serving eNB with information about the difference between the nominal UE maximum transmission power and the estimated transmission power for UL-SCH transmission for the Serving Cell. The reporting is done using the DPR MAC control element, which is sent in Msg3 together with a CCCH SDU. For EDT, the Data Volume in DPR MAC control element is set to zero. If enhancedPHR is configured and the UE supports extended power headroom reporting, the UE shall: - if the UE supports power class 14dBm and the MAC entity considers itself to be in enhanced coverage level other than 0: - report power headroom level using the DPR MAC control element; - else: - report extended power headroom level using the DPR MAC control element for Extended Power Headroom level reporting.