Power Headroom report in NSA

Despite activation, gNB never receives UL_SCH_LCID_SINGLE_ENTRY_PHR in NSA. At the same time, eNB signals an error for invalid received LCID with index 24 pointing to Dual Connectivity Power Headroom Report.

It is unclear if and under which circumstances PHR report for NSA goes through X2 interface instead through 5G ULSCH PDU. In case both gNB and eNB need to be modified to handle this scenario.

LTE Dual Connectivity Power Headroom Report MAC Control Element is described in section 6.1.3.6b of 36.321.

5G Power Headroom Reporting is in 5.4.6 of 38.321.