Analysis And Realization Of GGSN Charging Module

Development of data service will be a major driving force in the future and the charging of mobile network is becoming more and more important. As we know, the charging principles of packet switching and circuit switching are different. Charging of packet switching is based on traffic, while that of circuit switching is hour-based. Therefore, charging management of GPRS/WCDMA should be separated from that of GSM. GPRS will introduce in a newly developed charging gateway and rating center, which integrates with GSN net element, comprising a charging system. In such system, GGSN is responsible for collection of metering data and control of charging credibility. After years of operation and maintenance, current network has been indentified with a series of problems concerning charging of GPRS:(1) off-line phone bill is not able to be provided while phone is at roaming status; (2) poor risk control for real-time phone arrear; (3) severe bad debts issues; (4) unable to distinguish content charging, which constrains the development.This article is based on GGSN charging specifications from "3GPP/3GPP2", providing solutions to the above drawbacks. Focal points of this article reside at designing and realizing fundamental charging function supported by GGSN. They include "off-line charging module," " on-line charging module," " content charging module," and ultimately "phone bill generation module," etc. To improve GGSN software charging system’s chance of being reused, reduce system complexity and alleviate development work load and increase reliability, the system structure adopts three-layer structure design (including operating system layer, software-supported layer and application software layer.) As for module with charging function, technology from high-end software structure designed for concrete refinement process has been elaborated in a detailed manner. Code deciphering and analysis have been offered for some difficulties critical technology encounters.Off-line charging module:traditional off-line charging refers to off-line charging functions by GGSN software, with GGSN as the host terminal of RADIUS, recording all operations during customers’ use of network service, including types of service used, starting time and data traffic, etc.On-line charging module:it mainly realizes conversation-based charging. Such functional module operation is based on conversation charging request and conduct credibility control, which also provides services such as inquiry, updating account balance and accumulated amount.Content charging module:GGSN supports content-based charging function by conducting in-depth filtration and analysis of mobile users’ up and down-link data. APN configures different package to filter and analyze rules. Up and down-link data content transferred can be differentiate by rules.Phone bill generation module:GGSN creates G-CDR. Such functional module receives the phone bill output request of charging modular and output phone bill documents according to specific strategy.Due to word limitation of this article, the article introduces more about message flow, state machine, protocol suite and key data (threshold/timer/definition of basic data) of the design of submodule.