1. WF on Phase discontinuity issue in intra-band EN-DC with 1-PA
3GPP TSG-RAN WG4 NR #88bis
Chengdu, China, 8th – 12th October, 2018
Agenda: R
WF on Phase discontinuity issue in intra-band EN-DC with 1-PA
Intel, …

2. Background
Phase discontinuity issue has been identified [1] and RAN1 agreed to introduce a UE capability where UE can declare it cannot handle a phase discontinuity issue [2].

3. Background: Suggested UE behavior
Choose the following for UE behavior
Option 1 [3]:
When NR power would change during LTE sub-frame in intra-band EN-DC configuration is that NR power is kept constant so that NR power change do not to affect LTE reception on BS.
In case NR would transmit only on one of the two sub-frames it obviously cannot keep same power for both sub-frams or NR cannot keep constant power as it would violate emission requirements then in these cases NR sub-frame is dropped.
Option 2 [4]:
For the case of a phase discontinuity in intra-band EN-DC, intra-band CA, or FDM-based ULSUP with a single PA reference architecture, UE declares its capability if it cannot handle a phase discontinuity:
gNB could be scheduling the UE to avoid a phase discontinuity situation in case the UE declares that it cannot handle the phase discontinuity.
In case gNB forces to schedule the UE with a configuration which causes a phase discontinuity, UE behavior is not defined.

4. Way forward Choose Option 2
For the case of a phase discontinuity in intra-band EN-DC, intra-band CA, or FDM-based ULSUP with a single PA reference architecture, UE declares its capability if it cannot handle a phase discontinuity:
gNB could be scheduling the UE to avoid a phase discontinuity situation in case the UE declares that it cannot handle the phase discontinuity.
In case gNB forces to schedule the UE with a configuration which causes a phase discontinuity, UE behavior is not defined.
For intra-band EN-DC, intra-band CA, or FDM-based ULSUP, the capability is applicable even when NR is operated with the same numerology with LTE.
The capability is per band per combination.
Send reply LS to RAN1 and RAN2

5. Reference
[1] R , “On intra-band EN-DC power sharing assumption”, Intel
[2] R , “LS on NR-LTE Co-existence”, Intel, LGE
[3] R , “On UE Tx phase discontinuity in intra-band EN-DC”, Nokia
[4] R , “Phase discontinuity issue in intra-band EN-DC with 1-PA”, Intel