The WIN II Standard: Key Milestone for Prepaid Market
John Martin
09/01/2000
In early July, the Telecommunications Industry Association (TIA) published IS-826, otherwise known as the Wireless Intelligent Network (WIN) Phase II Prepaid Charging standard—or, more briefly, WIN II.
The revised standard offers several notable capabilities for prepaid services. It builds upon the initial standard, IS-771, published in December 1998, which established WIN architecture to support enhanced services in the mobile environment. WIN II enables a complete signaling-based approach to handling and controlling a prepaid call, without proprietary messages or routing the voice call to an adjunct switching platform. A WIN II-based billing platform receives messages from the network and returns instructions on how to handle the call, such as whether to let the call go through, deny the call or provide “low fund” warnings to subscribers in the middle of a call. This frees up the switch to perform its primary function of routing and controlling the call.
KEY BENEFITS
New features for prepaid services include improved scalability and efficiency of the billing platform, support for cross-platform roaming, and increased ability to offer enhanced call services.
Scalability
WIN II increases the scalability and efficiency of a prepaid platform. For example, in many traditional, non-WIN-based prepaid systems, the adjunct switching platform must carry the entire voice call, so the number of T-1 or E-1 trunks and ports in the prepaid system must grow proportionately with increased subscribers. The cost of such a system rapidly becomes prohibitive. In contrast, a WIN-based system is scalable, because calls are processed out-of-band—separately from the channel carrying the voice—using server-based technology and relational databases.
Roaming
The revised standard allows for prepaid roaming in a mixed infrastructure environment without the need for proprietary networks or platforms. It also guarantees that if a carrier invests in MSC/HLR (mobile switching center/home location register) infrastructure from multiple vendors, the technologies can be easily integrated. Prepaid roaming is key for subscribers who want services to match those of their postpaid counterpart—prepaid subscribers expect to be able to roam nationwide and across country borders.
New Services
With WIN II-based architectures, carriers can offer prepaid subscribers call waiting, call forwarding and three-way calling, which increase service usage and provide carriers with a new source of revenue. WIN II also enables the carrier to introduce new services more quickly, because service logic and subscriber data are centralized rather than distributed in all the mobile switching centers in the carrier’s network. When these services are invoked, messages are sent from the infrastructure to the billing platform. Therefore, a WIN II-based billing system can recalculate prepaid funds and time left for the call in real time.
For example, in order to support billing for enhanced services such as three-way calling, the prepaid system needs to be able to calculate the funds at the beginning of and throughout the call. If a subscriber begins a call with 15 minutes of funds remaining, and then initiates a three-way call 5 minutes later, the prepaid billing system must recalculate the amount of time the subscriber can stay on the call. Other services may be billed per use, because WIN II specifies a standard mechanism for the service platform to notify the billing system when the service is invoked.
WIN II-based systems calculate billing in real time, eliminating the opportunity for some types of fraud—in particular, the one-call exposure found in “hot billing” systems that process account status after the fact using call detail records (CDRs).
Timing
The first phase in implementing the revised standard will be through a software upgrade to the mobile infrastructure (MSC, HLR). It is expected that by the end of 2000, a few infrastructure vendors will have WIN II-compliant software available, with all manufacturers releasing their WIN II-compliant network hardware within another six months to a year. Prepaid billing systems that are WIN II-compliant should be available by the end of 2000. Carriers will then need to test interoperability of their mobile infrastructure and prepaid billing platform, which is expected to take around six months. Given this time line, the earliest carriers will begin looking at WIN II implementation in 2001.
Many market research analysts predict that the overall market will look seriously at WIN II in 2003–2004. Tole Hart, senior analyst for mobile communications at Dataquest, believes that “carriers will begin using WIN I and II standard equipment when the wireless traffic and use begins to mirror wireline traffic. We see the average minutes of use rising to over 500 minutes a month in 2004 in the United States; at that point you are seeing a good deal of wireless substitution of wireline services. As substitution continues to grow, carriers will need intelligent network systems to manage traffic and to offer landline type services, such as intelligent routing, effectively.”
Large carriers looking to expand their prepaid offerings will most likely be the first adopters of the new standard, with medium and small carriers following suit. In addition, large carriers already own huge networks with mixed infrastructures, so they will benefit immediately from the cross-platform interoperability.
ROI NOW, IMPLEMENT LATER?
Many carriers will face the question of when will be the best time to implement a WIN-based system. The real question is, how long can they afford to wait? Can their current system scale to meet a growing subscriber base? Are they looking to increase margins through enhanced services, weighed against the cost of implementing the new system? Carriers will not be caught in a crossfire of subsequent WIN versions, since the WIN II standard provides the platform for prepaid services interoperability. Any additions to the standard will be the layering of additional capability and will not disrupt a WIN II foundation.
Large carriers with mixed infrastructure will benefit immediately from implementing a WIN II-compliant environment. These carriers are eager to increase revenue by offering competitive prepaid services with roaming and new enhanced services enabled by the standard. According to Dataquest, “The wireless market has been increasingly competitive, with a multitude of new services such as flat rate local and long distance service, family plans and data service plans. The ability to offer these types of plans quickly ahead of a competitor or to catch up is important in gaining market share and reducing churn. WIN systems are a factor in getting these services to market quickly.”
Many U.S. carriers currently use trunk-based service bureaus, which can be expensive due to the cost per minute or per subscriber, and outright prohibitive to scale for large markets. With the WIN II standard, it may be more cost-effective for larger carriers to purchase a prepaid billing platform, especially with the overall wireless market reaching 50 percent saturation.
When specifying a system, carriers should look for one built from the ground up with a signaling-based architecture that accommodates the gradual implementation of the WIN II standard through software upgrades. (There are vendors currently who provide WIN-based systems that have experience scaling systems to support millions of subscribers and working with mixed infrastructure environments.) In addition, carriers should look for billing systems that in the interim phases can communicate with pre-WIN SS7 signaling-based systems, so that the carrier does not have to wait for all its roaming partners to implement WIN II to reap the benefits.
Small to medium carriers may want to consider a service bureau offering that gives them the functionality of the WIN II standard without the implementation costs. Although service bureaus are not as cost-effective as stand-alone billing systems for very large carriers, carriers with a smaller subscriber base may find that replacing their existing system with a WIN II-based system is difficult to justify.
BEYOND WIN II
By adding cross-platform support for roaming and enhanced services, the WIN II standard has opened the door to revenue-generating enhanced service offerings. The second part of WIN II, to be published later this year as IS-848, will provide enhanced charging and call-screening capabilities.
WIN III, expected to be published next year, will enable new capabilities by adding the functionality for location-based services. For example, a carrier will be able to offer maps automatically via any wireless device when a prepaid subscriber drives into a new roaming area, or provide advertisements for local services, including gas stations, restaurants and movie theaters. Location-based services also mean location-sensitive billing, so a carrier can offer pricing plans relevant to where a subscriber is calling from—lower prices, for example, when calling from the office or home area.
With mobile commerce (m-commerce) applications, subscribers will want to conduct transactions any time, anywhere—and WIN II helps make that possible. At the core of the leading prepaid billing systems are real-time rating engines to authorize, authenticate and account for transactions, which will be an essential component to support billing for mobile commerce. Such services require distinguishing between billing for voice and data, and as carriers look to bill for these services a real-time rating engine is essential.
Key Features of WIN II Prepaid Charging
· The mobile switching center can notify the billing system of call processing events.
· The billing system can control call termination.
· Subscribers can receive announcements of account balances and disconnect warnings.
· Billing systems can control and charge for enhanced services.
Subscribers can use enhanced services both in their home network and while roaming.
John Martin is senior director of product management at Corsair Communications, a provider of real-time business systems for the wireless industry. He can be contacted at martin@corsair.com.
Email this article
Add a comment
Printer version
Order reprints
RSS Feed
Bookmark article