Novel Algorithm to Recover the Lost CDR Information by Control and User Planes Separation in 4G and 5G

Abstract

In 3GPP networks, Charging Data Record (CDR) plays a very important role since it maintains the information related to the data usage which are used for billing the subscriber. In Evolved Packet Core (EPC) network, CDR can be generated by both Serving Gateway (SGW) and Packet Data Network Gateway (PGW) where both Control Plane (CP) messages which represents the messages related to the creation of the Packet Data Network (PDN) sessions and the User Plane (UP) messages which represents the actual data (Internet data from device or voice/video calls) are transferred. With Control and User Plane Separation (CUPS) architecture, the CP messages will be handled by the CP node (GW-C) and UP messages will be handled by the UP node (GW-U). Similar architecture enhancement of CP and UP separation is continued towards 5G also. In CUPS system, charging information is calculated at the UP node based on actual usage and will be conveyed to CP node in Sx messages using Packet Forwarding Control Protocol (PFCP) via UDP. Loss of this CDR information in between the CP and UP nodes due to any network issue will directly impact the revenue and reputation of the operator. In the current paper we have discussed some of the scenarios which can result in CDR information loss between CP and UP nodes (observed in the commercial deployed networks) and proposed a novel algorithm to recover the same. The simulation result also represents that with the proposed idea more than 95% of the missing information can be recovered with minimal increase in the network load.