In LTE Core Network, all data plane traffic must go through a single node type called Packet Data Network Gateway (P-GW). This centralized architecture is advantageous in terms of operation and management. Yet, it could potentially pose a severe limitation when there is a huge amount of backhaul traffics in 5G.
The following figure illustrates the existing LTE Core architecture and the potential issues when there is a significant amount of traffic increase and Some of the engineering trade-offs and limitations of today’s LTE-SAE:
- Potential traffic bottleneck at P-GW.
- H/W dependency of network functions.
- Closed & operator-driven VAS.
At present, the maximum cell capacity for a 5G base station is expected to be higher than several tens of Gbps. Given that many base stations will be densely deployed and centralized for Cloud-RAN, mobile backhaul traffic is expected to exceed even more than several hundred Gbps.
Therefore, the core network functions and the overall architecture must be enhanced to better support various 5G services (such as mobile broadband, mission-critical IoT, and massive IoT) even when the network is congested due to frequent traffic surges.
In order to enhance the existing architecture to better support scalability and performance, 5G defines Cloud Core architecture and its components below.
- Flat architecture for distributed traffic delivery.
- Virtualized S/W, independent from H/W.
- Open architecture / API for innovative services.
Source: SK Telecom