Measurement Gap for EN-DC Scenarios

5G NR
, , ,
1

Hi everyone, I have some questions regarding measurement gap for NSA HO scenarios. I will be glad to have some comments from you, thanks in advance;

  1. In M-eNB to M-eNB HO with SN Change/Modification procedure, I need some information about how measurement gap should be coordinated between 4G and 5G. I mean, if UE is configured with measurement gap for 4G neighbor cell measurements, after NR A2 report is delivered to UE(while 4G measurement gap is active), how measurement gap on NR side should be configured? Should the new measurement gap be overwritten to the existing 4G gap?
  2. For SN Initiated SN Change/Modification or M-eNB to M-eNB HO with SN Change/Modification, how 5G measurement gap should be delivered to UE? As far as I understand, according to TS 36.331, measurement gap can be delivered to UE with both MeasGapConfig (with LTE-type configuration) or with nr-SecondaryCellGroupConfig(5G-type configuration)?
  3. What is the use case of MeasGapSharingConfig for NSA HO scenarios? Is that IE used for balancing the NR intra-freq measurements and measurement gap configuration for inter-freq cells?
  4. As far as I understand, according to O-RAN WG5 NR C-plane specifications sec 5.6.7.3, before UE is informed about CU-configured measurement gap, the meas gap configuration is delivered to DU side. In that case, if UE can not decode RRC Reconfig for some reason, scheduler is interrupted for this UE uselessly. Wouldn’t it be more logical to configure UE with measurement gap first and then configure the scheduler to interrupt scheduling for this UE?
  5. As far as I understand from O-RAN WG5 NR C-plane specifications sec 5.6.7.3, it seems that measurement gap can be configured first on UE side before DU-MAC scheduler interrupts scheduling (scheduler suspends scheduling until UE sends RRC Conn Reconfig Complete) or DU-MAC stops scheduling UE first (before UE sends RRC Conn Reconfig Complete). It seems that the first option will be more suitable to inform UE about measurement gap and stop scheduling UE after it sends RRC Conn Reconfiguration Complete, since in case of any RRC Reconfig decoding issue, DU does not interrupt scheduling uselessly. What is your opinion, will it be appropriate to stop scheduling UE after it sends RRC Conn Reconfig Complete message?