PCRF refers to "Policy and Charging Rules Function". It is a key element within the Policy and Charging Control (PCC) framework. It is responsible for making policy decisions and generating charging rules for the network.

The PCRF is responsible for making policy decisions based on various factors, such as subscriber profiles, service requirements, network conditions, and operator policies. Accordingly it determines the appropriate Quality of Service (QoS) parameters, traffic management rules, and other policies to be applied to the subscriber's data sessions.

In addition, the PCRF generates the charging rules that is responsible for subscriber's usage charging.

The coordination between the PCRF and other network elements, such as the PCEF and the OCS, ensures the consistent of policies and charging across the mobile network.