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PCF Charging Software Design Architecture

Note

Author: Andy Chen (CTFang)
Date: 2024/05/07

PCF: Policy Control Function

Relative specs:

  • TS 29.507 Access and Mobility Policy Control Service
  • TS 23.503 Policy and Charging Control Framework for the 5G System (5GS)
  • Ts 29.513 Policy and Charging Control Signalling flows and QoS parameter mapping
  • Ts 23.255 Telecommunication management; Charging management; 5G data connectivity domain charging

The 3GPP defines the FBC(Flow-Based Charging) and QBC (QoS-Based Charging).

However, free5GC v3.4.1 supports FBC only.

RatingGroup Allocate

PDU session establishment

PDU session establishment, described in 3GPP TS 32.255 clause 5.2.2.2.2

Charging on PDU Session is achieved by FBC charging, with specific rating group/service identifier:

  • The rating group would be allocated by PCF during SM Policy Authorization (Step 6).

    • Get chargingData from MongoDB collection policyData.ues.chargingData.
    • Allocate rating group to each charging rule.
    • Create new chargingData with rating group in MongoDB.
    • Create PCC Rule for charging with rating group, SDF template, and charging method.
    • Make Decision from PCC Rule to SMF.

  • When PCF HandleDeleteSmPolicyContextRequest, the new chargingData with rating group would be deleted.

CHF

CHF would use rating group from MongoDB (policyData.ues.chargingData) to calculate the usage and grant quota.

  • ABMF (Account Balance Management Function)
  • Rating Function

pcf_charging

Others