Discuss the PCF in 5G as compared to the PCRF in 4G?
By definition PCF stands for Policy Control Function in 5G. It is a Network Function (NF) that provides policy control and charging rules for 5G services and applications. It interacts with other network functions, such as AMF, SMF, UPF, UDM, AUSF, and AF, through service-based interfaces. PCF is responsible for authorizing the quality of service (QoS) and allocating the QoS flow identifiers (QFI) for each data flow. PCF also supports network slicing, roaming, and mobility management. PCF can collect subscriber metrics and provide real-time management of subscribers, applications, and network resources based on service provider–configured business rules.
PCRF stands for Policy and Charging Rules Function in 4G. It is a node that operates in real time to determine policy rules in a multimedia network. It operates at the core of the network and has access to subscriber databases and other specialized functions, such as charging system. PCRF provides QoS authorization and enforces policy rules on the PCEF.
So based on the definitions of PCF and PCRF, we can see that PCF in 5G works similarly to the PCRF on a 4G network but with enhanced capabilities. The PCF can uniformly control policies across 2G, 3G, 4G, and 5G networks. The cloud-based PCF can be used together with the existing ATCA-based PCRF, facilitating smooth transformation of networks.
Policy data can be smoothly migrated to, and service configurations are centrally managed by the PCF. Subscribers can be migrated from 4G to 5G networks first. Then, we can gradually upgrade 4G sites to 5G to achieve full 5G coverage.
The provisioning system can be connected to the PCF, so that the PCF can uniformly deliver service provisioning instructions.
The EMS can be selected based on terminal capabilities. 4G and 5G signaling messages can be processed based on terminal capabilities and network coverage.
