It enables efficient policy control and management, facilitating network behavior control, network slicing, roaming support, UE activities, and communication with other 5G core network functions. It acts as a control plane Network Function (NF) responsible for managing policies that regulate various aspects of the network. These policies encompass a wide range of functions, including quality of service (QoS), network resource allocation, authentication, mobility, security and more [1].

PCF performs the same/similar function as the PCRF in 4G networks.

Accesses subscription information for policy decisions

Static as well as dynamic policies

Seamless session continuity for inter-RAT handover

Key Functions

• Policy Decision: The PCF makes policy decision based on user subscription information, network resource availability, and other factors.
• Policy Enforcement: The PCF enforces policy decisions by providing rules and instructions to other network functions, such as Session Management Function (SMF) and User Plane Function (UPF).
• QoS Management: The PCF manages QoS policies, ensuring that user data is treated according to the required QoS parameters.
• Charging and Billing: The PCF provides charging and billing information to the Charging Function (CHF), enabling accurate billing and revenue management.
• Network Resource Management: The PCF manages network resources, such as bandwidth and latency, to ensure efficient utilization and allocation.

PCF Procedures

1. Policy Decision Procedure
2. Policy Enforcement Procedure
3. QoS Management Procedure
4. Charging and Billing Procedure

Types of PCF

1. Centralized PCF: A centralized PCF makes policy decisions for multiple network functions, providing a centralized point of control
2. Distributed PCF: A distributed PCF is co-located with other network functions, providing a decentralized point of control and reducing latency.

Policy Types

1. Static Policies: Static policies are predefined rules that are applied to all users and network functions.
2. Dynamic Policies: Dynamic policies are created in real-time based on changing network conditions and user behavior.

Bibliography:

1. https://www.digitalroute.com/resources/glossary/pcf-5g-policy-control-function/
2. https://www.iplook.com/products/5gc-pcf