PCRF is an important entity in the LTE core network domain, initially introduced in 3gpp rel 5. It is mainly responsible for policy-making and control decisions. In simple words, if a user needs better quality of service (lets suppose in case of VoLTE ) then it is the responsibility of PCRF to initiate QoS with instructions from IMS. The functionality is listed below
- Provide QoS information to packet gateway
- Dynamically manage and control data sessions. Example: For VoIP session, PCRF will initiate dedicated bearer dynamically
- Enforce minimum QoS parameters
- Determine charging policy for packets
