Introduction to Dual Connectivity (DC) in E-UTRAN?

Dual Connectivity (DC) in E-UTRAN allows a multi-Rx/Tx UE in RRC_CONNECTED mode to use radio resources provided by two distinct schedulers located in two nodes. These nodes are connected via a non-ideal backhaul over the X2 interface. In DC, a UE connects to one Master eNB (MeNB) and one Secondary eNB (SeNB). So, now let us Understand Dual Connectivity (DC) in 5G Networks along with Accurate Best wireless site survey software, site survey tools for wireless networks & Indoor cellular coverage walk testing tool and Accurate LTE RF drive test tools in telecom & RF drive test software in telecom in detail.

Roles of eNBs in DC

In DC, the eNB can either act as a Master eNB (MeNB) or a Secondary eNB (SeNB).  There are three types of bearers: MCG bearer, SCG bearer, and split bearer.

Types of Bearers:

MCG Bearer: This bearer’s radio protocols are only located in the MeNB, utilizing only MeNB resources.

SCG Bearer: This bearer’s radio protocols are solely in the SeNB, using SeNB resources.

Split Bearer: This bearer’s radio protocols are in both the MeNB and SeNB, utilizing resources from both.

MR-DC with 5GC can be classified into three architectures:

E-UTRA-NR Dual Connectivity (NGEN-DC): Here, a UE connects to one ng-eNB (MN) and one gNB (SN). The ng-eNB is linked to the 5GC, and the gNB is connected to the ng-eNB via the Xn interface.

NR-E-UTRA Dual Connectivity (NE-DC): In this setup, a UE connects to one gNB (MN) and one ng-eNB (SN).

NR-NR Dual Connectivity (NR-DC): In this architecture, a UE connects to one gNB (MN) and another gNB (SN).

What are the deployment scenarios for EN-DC?

EN-DC architecture is ideal for deployment scenarios introducing 5G NR without 5GC. Here, control plane anchors are in the LTE RAN, with the S1-C interface terminated by eNB. This architecture is further divided into three networking types:

Option 3 Networking: The eNB terminates the S1-U interface, and the NR gNB lacks any interface to EPC. Traffic converges at the eNB PDCP layer and is divided from the eNB to the gNB via the X2 interface. This setup requires substantial traffic handling and computing power from the eNB, necessitating hardware upgrades to prevent bottlenecks.

Option 3A Networking: Traffic splits at the core network, with service bearers in LTE or 5G NR. This setup allows eNB to offload high-throughput or low-latency services to the NR Node, reducing processing demands on itself.

Option 3X Networking: The gNB has an S1-U interface to EPC, with traffic converging at the gNB PDCP layer and dividing from the gNB to the eNB via the X2 interface. This architecture leverages the high performance of 5G NR, minimizing the need for extensive upgrades to the existing RAN and transport network.

NGEN-DC Scenarios

How does NGEN-DC work?

In NGEN-DC, a UE connects to an evolved eNB (MN) and a gNB (SN). The evolved eNB connects to the new 5GC via NG-C and NG-U interfaces, and the gNB is connected to 5GC via the NG-U interface.  This architecture supports scenarios where the LTE RAN has been upgraded to support 5GC.

NE-DC Scenarios

What is the NE-DC architecture?

In NE-DC, a UE connects to one gNB (MN) and one evolved eNB (SN). The gNB connects to the new 5GC via NG-C and NG-U interfaces, and the evolved eNB connects to 5GC via the NG-U interface.  This architecture is suitable for scenarios where 5G NR provides continuous coverage. Control plane anchors are always located in the 5G NR, leveraging its superior capabilities and capacity.

Key Takeaways:

Dual Connectivity (DC): Allows UEs to utilize resources from two schedulers in two distinct nodes, enhancing connectivity and resource utilization.

MR-DC with EPC and 5GC: Offers flexible architecture options to integrate 5G NR and LTE, ensuring seamless connectivity and efficient resource use.

EN-DC and NGEN-DC Scenarios: Provide versatile deployment scenarios to accommodate varying network requirements, ensuring optimal performance and minimal infrastructure upgrades.

Understanding the intricacies of Dual Connectivity and its various architectures is crucial for deploying efficient and robust 5G networks. By leveraging the strengths of both LTE and 5G NR, these architectures ensure seamless connectivity and optimal resource utilization, paving the way for the future of mobile communication. Also read similar articles are from here.