Tariff Period

Description

The Tariff Period is a concept in 3GPP charging management that defines a specific time interval within a calendar day during which a particular tariff is applied. It is characterized by two key parameters: the switch-over time, which marks the beginning of the period, and the tariff that is applied after the switch-over. This allows operators to implement time-based pricing models, such as peak and off-peak rates, where the cost of a service varies depending on the time of day. The Tariff Period is defined in multiple 3GPP specifications, including TS 32.240, TS 32.250, TS 32.251, TS 32.272, TS 32.273, TS 32.276, TS 32.278, and TS 32.293, which cover charging management, charging architecture, and specific charging scenarios for various services.

In practice, a Tariff Period is used by the charging system to determine the applicable rate for a communication event based on the time it occurs. For example, a network may define a peak period from 8:00 AM to 6:00 PM with a higher tariff, and an off-peak period from 6:00 PM to 8:00 AM with a lower tariff. The switch-over time is the exact moment when the tariff changes, such as 6:00 PM. The charging system evaluates the current time against the defined Tariff Periods to select the appropriate tariff. This evaluation can occur at the start of a session, during a session if the period changes, or at the end of a session for offline charging. The Tariff Period is often used in conjunction with other tariff parameters, such as the Tariff Sequence, to handle complex charging scenarios where multiple tariffs apply sequentially within a single communication event.

The Tariff Period is a fundamental building block of the charging architecture. It is typically stored in the charging system's tariff tables or databases, which are managed by the operator. The charging functions, such as the Charging Trigger Function (CTF) or the Charging Data Function (CDF), retrieve the applicable Tariff Period based on the current time and the subscriber's profile. For online charging, the Online Charging Function (OCF) uses the Tariff Period to rate the service usage in real-time and to authorize the session based on the subscriber's available credit. For offline charging, the Charging Gateway Function (CGF) uses the Tariff Period to generate Charging Data Records (CDRs) that reflect the correct tariff for each portion of the session. The Tariff Period also supports the concept of multiple tariff periods within a day, allowing for fine-grained time-based pricing.

The implementation of Tariff Periods requires accurate time synchronization across network elements to ensure that the switch-over times are consistently applied. This is particularly important in multi-vendor environments where different network elements may be involved in the charging process. The 3GPP specifications provide guidelines for time synchronization and for the handling of tariff period transitions, including the generation of partial CDRs when a session spans multiple tariff periods. The Tariff Period concept also supports the use of different calendars, such as public holidays or special event days, where different tariff periods may apply. This flexibility allows operators to create sophisticated pricing strategies that can be tailored to market conditions and regulatory requirements.

In summary, the Tariff Period is a critical component of 3GPP charging management that enables time-based differential charging. It provides a standardized way to define and apply tariffs based on the time of day, ensuring that charging is accurate and consistent across the network. Its widespread adoption in numerous specifications and its continued presence from Release 8 to Release 19 underscore its importance in both traditional and advanced mobile networks.

Purpose & Motivation

The Tariff Period exists to enable time-based differential charging in mobile networks, allowing operators to apply different tariffs at different times of the day. This capability is essential for implementing peak and off-peak pricing, which helps operators manage network congestion, optimize resource utilization, and offer competitive pricing to subscribers. Before the standardization of Tariff Periods, charging systems often used proprietary or ad-hoc methods for time-based pricing, leading to inconsistencies and interoperability issues. The 3GPP defined the Tariff Period to provide a clear and standardized framework for time-based charging, ensuring that all network elements can consistently determine and apply the correct tariff.

The primary problem it solves is the need to vary the cost of services based on the time of day. For example, operators may want to encourage off-peak usage by offering lower rates during periods of low network load, or they may want to charge higher rates during peak hours to reflect the higher cost of providing the service. The Tariff Period provides a simple yet powerful mechanism to achieve this by defining specific time intervals and the associated tariffs. It also supports the generation of accurate billing records that reflect the time-based pricing, which is crucial for revenue assurance and customer satisfaction.

Historically, as mobile networks evolved and competition increased, operators needed more flexible pricing models to differentiate their offerings. The Tariff Period was introduced in Release 8 as part of the broader charging management framework, and it has been maintained and refined in subsequent releases. Its continued presence in Release 19 demonstrates its enduring relevance, even as networks move towards 5G and beyond. The Tariff Period concept has also been adapted to support new services and business models, such as IoT and network slicing, where time-based charging may be combined with other parameters like data volume or service type.