Dual Connectivity architecture options(MR-DC)

Dual Connectivity architecture options(MR-DC)

Multi-Radio Dual Connectivity:

Multi-Radio Dual Connectivity (MR-DC) is a generalization of the Intra-E-UTRA Dual Connectivity (DC) described in TS 36.300 [2], where a multiple Rx/Tx capable UE may be configured to utilize resources provided by two different nodes connected via non-ideal backhaul, one providing NR access and the other one providing either E-UTRA or NR access. One node acts as the MN and the other as the SN. The MN and SN are connected via a network interface and at least the MN is connected to the core network.

MR-DC is designed based on the assumption of non-ideal backhaul between the different nodes but can also be used in case of ideal backhaul.

MR DC two type.

1. MR-DC EPC: EN-DC

2. MR DC 5GC: NGEN-DC , NE-DC & NR-DC

MR-DC EPC: E-UTRAN supports MR-DC via E-UTRA-NR Dual Connectivity (EN-DC), in which a UE is connected to one eNB that acts as an MN and one en-gNB that acts as an SN. The eNB is connected to the EPC via the S1 interface and to the en-gNB via the X2 interface. The en-gNB might also be connected to the EPC via the S1-U interface and other en-gNBs via the X2-U interface.

MR-DC with the 5GC :

E-UTRA-NR Dual Connectivity:
NG-RAN supports NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC), in which a UE is connected to one ng-eNB that acts as a MN and one gNB that acts as a SN. The ng-eNB is connected to the 5GC and the gNB is connected to the ng-eNB via the Xn interface.

E-UTRA-NR Dual Connectivity
NG-RAN supports NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC), in which a UE is connected to one ng-eNB that acts as a MN and one gNB that acts as a SN. The ng-eNB is connected to the 5GC and the gNB is connected to the ng-eNB via the Xn interface.

NR-NR Dual Connectivity
NG-RAN supports NR-NR Dual Connectivity (NR-DC), in which a UE is connected to one gNB that acts as a MN and another gNB that acts as a SN. The master gNB is connected to the 5GC via the NG interface and to the secondary gNB via the Xn interface. The secondary gNB might also be connected to the 5GC via the NG-U interface. In addition, NRDC can also be used when a UE is connected to two gNB-DUs, one serving the MCG and the other serving the SCG, connected to the same gNB-CU, acting both as a MN and as a SN

EN-DCNGEN-DCNE-DCNR-DC
Master nodeeNBeNB (ng-eNB)gNBgNB
Secondary
node
gNB (en-gNB)gNBeNB (ng-eNB)gNB
Interface used
between MN
and SN
X2XnXnXn
Core Network
used
EPC5GC5GC5GC
Control Plane
connection
between CN
and RAN
S1-C interface
between MN
and MME
N2 interface
between ng-eNB
and AMF
N2 interface
between gNB
and AMF
N2 interface
between gNB
and AMF
User Plane
connection
between CN
and RAN
S1-U interface
between MN
and S-GWand
optionally
between SN and
S-GW
N3 interface
between ng-eNB
and UPF and
optionally
between gNB
and UPF
N3 interface
between gNB
and UPF and
optionally
between ng-eNB
and UPF
N3 interface
between gNB
acting as an MN
and UPF and
optionally
between gNB
acting as an SN
and UPF