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Introduction

While there are many technologies involved in deploying mobile prepay (prepaid wireless service), this paper provides and introduction to the various types of mobile prepay deployments and the associated technologies. For more information, see www.mobileprepay.com and the associated detailed reports that address mobile prepay technology, business issues, and market prospects.

Research

Wholesale Mobile Report

Secrets of MVNO Success

Mobile in Minute papers

Point Solutions

Point solutions involve an adjunct piece of equipment that is used to provide call control, database functions, administrative functions and call processing. These are called "point" solutions as all calls must traverse a single network element or "point". The advantage of a point solution is that they are typically less expensive to set up for an initial or limited deployment. However, they do not necessarily scale as well as other solutions when large numbers of prepay customers are added to the system. An example of a point solution would is a Service Node based solution, which are often deployed based on programmable switch technology.

ISUP based Solutions

ISUP based solutions prepay solutions typically utilize an innovative network kluge known as ISUP-loop back. With ISUP loop-back signaling, the SCP contains software logic to "spoof" the mobile switch. The SCP tricks the mobile switch, making it appear to be signaling with another switch for call set-up via ISUP (as normal), when in fact it is performing database operations necessary to process prepay calls. ISUP based solutions of this type are considered to be a form of point solution as every call must go through the single point at the voice loop-back trunks.

Intelligent Network based Solutions

These fall into two categories: Proprietary IN and standards based IN solutions.

Proprietary solutions are limited due to its proprietary (vendor specific) nature, roaming is problematic. Roaming can only occur between like switch types that have the same software logic and triggers armed. This includes implementations that utilize proprietary extensions of the INAP standard.

Standards based IN solutions are enabled by the WIN and CAMEL standards for ANSI-41 and GSM mobile networks respectively. These IN standards provide capabilities for TCAP based standard prepay deployment. They provide a major improvement over proprietary TCAP solutions by allowing roaming to take place wherever serving carriers support the necessary triggers and software logic. This means that, in order to provide service to prepay callers, the serving system must support WIN/CAMEL standards, even if the serving market does not support WIN/CAMEL based prepay for its own (home) customers.

Handset Solutions

These methods involve the placement of intelligence in a mobile terminal to determine the capabilities and account status of the prepay subscriber. Handset solutions fall into two broad categories based largely on mobile network standards: Smart Card based solutions, such as Subscriber Identity Module (SIM) solutions based on GSM, and proprietary handset based solutions.

Hybrid Solutions

A hybrid solution example would be exemplified by a SIM based solution for basic prepay call processing with a TCAP based IN complement for value-added services such as location sensitive billing. It is likely that many GSM operators will adopt this approach as they migrate to a full CAMEL based IN architecture over time.

Call Detail Record (CDR) based Solutions

CDR based solutions utilize a near real-time based process to track mobile usage by prepay customers. This solution has the advantage of low cost compared to other solutions. As CDRs are monitored after a call is placed, this solution can sometimes allow unbillable usage on the last call (prior to the system detecting a zero account balance and initiating a disconnection).

Additional Resources:

Books about: Billing, OSS, and BSS

For more information
Mobile Prepay: www.MobilePrepay.com