Efficient Methods for Bearer Traffic Flow Migration in NG-RAN

In NG-RAN (Next Generation Radio Access Network), Radio Access entity usually referred to as eNB in LTE has evolved into 2 entities namely, NG-DU (Next Generation Distribution Unit) and NG-CU (Next Generation Central Unit). NG-CU is realized as a cloud-based platform to exploit inherent optimization of the cloud features such as ease of load-balancing and to support scaling of resources. In Next generation specifications, bearer is managed as GTP (GPRS Tunneling Protocol) tunnels from NG-DU to NG-CU VNF (Virtual Network Function) component and from NG-CU VNF component to NG-Core. When scalability aspects are applied at NG-CU, GTP tunnels have to be migrated from one VNFC to the other. Migration of GTP tunnels results in call disruption. To address this challenge we propose 2 simple yet effective methods. The 1st method introduces a new service entity in NG-RAN architecture which acts as a GTP-Arbitrator towards both NG-DU and NG-Core. The 2nd method introduces new Path Switch signaling where nodes/entities in NG-DU, NG-CUs VNF components and NG-Core need to coordinate synchronously for the migration of bearer contexts. In this paper we analyze the merits of these 2 methods during migration of traffic bearers across CUs VNF components under different traffic conditions.