VBC

Volume Based Charging

Services
Introduced in Rel-15
Volume Based Charging (VBC) is a 3GPP charging mechanism that calculates service costs based on the total data volume consumed by a user, rather than connection time or flat rates. It is defined in TS 24.147 and is fundamental for monetizing data services, enabling flexible billing models like tiered data plans. This method is crucial for operators to implement fair usage policies and for users to understand their data consumption costs.

Description

Volume Based Charging (VBC) is a standardized online charging system (OCS) function within the 3GPP architecture, specified primarily in TS 24.147. It operates by monitoring and metering the quantity of data (in bytes) transferred during a user's data session, such as a Packet Data Protocol (PDP) context in 4G or a PDU Session in 5G. The charging mechanism is integrated with core network elements like the Policy and Charging Rules Function (PCRF) in 4G or the Policy Control Function (PCF) in 5G, which enforce policies, and the Charging Data Function (CDF) or Online Charging System (OCS), which collects charging data records (CDRs) or performs real-time credit control. When a user initiates a data session, the network triggers a charging session where the serving gateway (SGW) or user plane function (UPF) reports data usage volumes to the charging system at configured intervals or thresholds. The OCS then deducts credit from the user's account based on the reported volume, potentially applying different tariff rates depending on the service, time of day, or network conditions. This process allows for real-time quota management, where the network can grant a specific data volume quota, and upon its exhaustion, request a new quota or terminate/restrict the session based on operator policy. VBC is a cornerstone of modern data service monetization, enabling precise, granular billing that aligns with actual resource consumption.

Purpose & Motivation

Volume Based Charging was created to address the limitations of traditional charging models, such as duration-based charging (common in voice calls) or flat-rate billing, which were ill-suited for bursty, packet-switched data services. As mobile networks evolved from circuit-switched voice to packet-switched data (GPRS, 3G, 4G, 5G), data usage became highly variable, making time-based charging unfair and flat rates unsustainable for operators due to unpredictable network load. VBC provides a fair and accurate method to charge users precisely for the amount of data they consume, which is essential for the commercial success of mobile broadband. It enables operators to offer flexible tariff plans, such as pay-per-use, tiered data bundles, and shared data plans, which cater to diverse user needs and consumption patterns. Historically, its introduction supported the shift from voice-centric to data-centric revenue models, allowing operators to manage network resources efficiently while providing transparency to customers. Without VBC, implementing complex data plans, fair usage policies, and real-time spending controls would be significantly more challenging.

Key Features

  • Charging based on metered data volume (uplink, downlink, or total)
  • Real-time credit control and quota management via OCS
  • Integration with policy control (PCRF/PCF) for service-aware charging
  • Support for different tariff rates applied to specific data flows or services
  • Generation of detailed Charging Data Records (CDRs) for billing
  • Capability to trigger notifications or actions upon quota exhaustion

Evolution Across Releases

Rel-15 Initial

Introduced Volume Based Charging as a defined mechanism in TS 24.147, establishing the framework for charging based on data volume consumption within the 5G system architecture. It integrated with the 5G core's PCF and CHF (Charging Function) to support service-based interactions and network slicing.

TS 24.147

Defining Specifications

SpecificationTitle
TS 24.147 3GPP TS 24.147