Reporting power headroom in multiple connectivity next generation networks

1. A method by a base station for receiving power headroom reporting from a user equipment (UE) in a Multi-Radio Access Technology (RAT)-Dual Connectivity (MR-DC) scenario, the method comprising:

receiving a DC Power Headroom Report (PHR) Medium Access Control (MAC) Control Element (CE) from the UE, the DC PHR MAC CE having a fixed number of octets with cell index fields for indicating whether a power headroom (PH) for a serving cell with a corresponding cell index is reported;

wherein the fixed number of octets is independent of a highest secondary Cell Index (SCellIndex) for serving cells with configured uplinks.

2. The method of claim 1 , wherein the fixed number of octets is four for the DC PHR MAC CE.

3. The method of claim 1 , wherein a logical channel identifier (LCID) identifies the DC PHR MAC CE for both single-octet bitmap with cell index fields and four-octet bitmap with cell index fields.

4. The method of claim 1 , wherein the DC PHR MAC CE is identified by a MAC PDU subheader including at least one of:

an LCID for reporting the DC PHR MAC CE using a single-octet bitmap; and

an LCID for reporting the DC PHR MAC CE using a four-octet bitmap.

5. The method of claim 1 , wherein the DC PHR MAC CE is identified by a MAC PDU subheader with an LCID for reporting the DC PHR MAC CE using a four-octet bitmap when the base station is a secondary node.

6. The method of claim 1 , wherein, when the base station is a secondary node, the DC PHR MAC CE is identified by a MAC PDU subheader including at least one of:

an LCID for reporting the DC PHR MAC CE using a one-octet bitmap; and

an LCID for reporting the DC PHR MAC CE using a four-octet bitmap.

7. The method of claim 1 , wherein the base station is an evolved NodeB (eNB).

8. A base station configured to receive a power headroom report from a user equipment (UE) in a Multi-Radio Access Technology (RAT)-Dual Connectivity (MR-DC) scenario, the base station comprising:

one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and

at least one processor coupled to the one or more non-transitory computer-readable media, and configured to execute the computer-executable instructions to:

receive a DC Power Headroom Report (PHR) Medium Access Control (MAC) Control Element (CE) from the UE, the DC PHR MAC CE having a fixed number of octets with cell index fields for indicating whether a power headroom (PH) for a serving cell with a corresponding cell index is reported;

wherein the fixed number of octets is independent of a highest secondary Cell Index (SCellIndex) for serving cells with configured uplinks.

9. The base station of claim 8 , wherein the fixed number of octets is four for the DC PHR MAC CE.

10. The base station of claim 8 , wherein a logical channel identifier (LCID) identifies the DC PHR MAC CE for both single-octet bitmap with cell index fields and four-octet bitmap with cell index fields.

11. The base station of claim 8 , wherein the DC PHR MAC CE is identified by a MAC PDU subheader including at least one of:

an LCID for reporting the DC PHR MAC CE using a single-octet bitmap; and

an LCID for reporting the DC PHR MAC CE using a four-octet bitmap.

12. The base station of claim 8 , wherein the DC PHR MAC CE is identified by a MAC PDU subheader with an LCID for reporting the DC PHR MAC CE using a four-octet bitmap when the base station is a secondary node.

13. The base station of claim 8 , wherein, when the base station is a secondary node, the DC PHR MAC CE is identified by a MAC PUD subheader including at least one of:

an LCID for reporting the DC PHR MAC CE using a one-octet bitmap; and

an LCID for reporting the DC PHR MAC CE using a four-octet bitmap.

14. The base station of claim 8 , wherein the base station is an evolved NodeB (eNB).

15. A method by a base station for receiving power headroom reporting from a user equipment (UE) in a Multi-Radio Access Technology (RAT) Dual Connectivity (MR-DC) scenario, the method comprising:

receiving a Multiple Entry (ME) Power Headroom Report (PHR) MAC Control Element (CE) from the UE, the ME PHR MAC CE based on information received from a network, the ME PHR MAC CE having a fixed number of octets with cell index fields for indicating whether a power headroom (PH) for a serving cell with a corresponding cell index is reported,

wherein the fixed number of octets is determined based on information received from the network; and

wherein the information received from the network comprises one of a highest serving cell index (ServCellIndex) for serving cells with configured uplinks, and a stop value of a secondary node serving cell index range.

16. The method of claim 15 , wherein a bit in the ME PHR MAC CE is used to indicate whether a PH of a supplemental uplink (SUL) associated with a serving cell is present in the ME PHR MAC CE, and wherein the SUL is supplemental to an original uplink (OUL) associated with the serving cell.

17. The method of claim 16 , wherein whether the PH of the SUL associated with the serving cell is present is based on at least one of:

one or more sounding reference signal (SRS) configurations for the SUL associated with the serving cell; and

one or more allocated resources for uplink data transmission on the SUL associated with the serving cell.

18. The method of claim 15 , wherein a bit in the ME PHR MAC CE is used to indicate whether one or more original uplink (OUL) PHs of serving cells are reported or one or more supplemental uplink (SUL) PHs of serving cells are reported.

19. The method of claim 15 , wherein the ME PHR MAC CE is identified by a MAC PDU subheader including at least one of:

an LCID for reporting the ME PHR MAC CE for one or more supplemental uplinks (SULs) using a single-octet bitmap; and

an LCID for reporting the ME PHR MAC CE for one or more SULs using a four-octet bitmap.

20. The method of claim 15 , wherein the base station is a next generation NodeB (gNB).