WIN or Lose

Will WIN be able to cross over to Internet offerings? WIN technology is an investment that service providers must make to leverage network assets and deploy valued services. Patterned after wireline-based IN technology, WIN technology was designed similarly to separate call control and service logic from switching functions. The principal difference between WIN and wireline-based technologies such as advanced IN (AIN) and IN application part is that WIN considers mobile-management functions necessary to provide services while roaming. Most importantly, WIN enables delivery of applications such as location services and m-commerce applications for TDMA and CDMA networks.

First Things First Conceived in the 1990s, WIN promised to provide many benefits including improved network efficiency and advanced services as well as more flexible and less expensive services deployment. Before all of these promises could be realized, however, service providers had to make certain infrastructure improvements. One of those improvements was to deploy network-based (or standalone) HLRs. Separating the HLR function from the MSC allowed the MSC to perform its primary function - switching - more efficiently. This model proved to be more cost-effective than the prior (combined MSC/HLR) arrangement because many MSCs could share a single HLR via the SS7 network. Although standalone HLRs did not require WIN protocols, this architecture provided valuable operations experience and improved network topology for providers to deploy network-based services hosted on a service control point (SCP).

The first phase of WIN standards, IS-764 and IS-771, was available following network-based HLR deployment. Although these standards were driven by the need to support services such as calling-name presentation (CNAP), voice-control services (VCS) and incoming-call screening (ICS), WIN is designed to standardize capabilities, not services. This means that WIN protocols and procedures are intended for use with a variety of different services.

To date, none of these initial services has met with great com-mercial success. CNAP is handled directly in the mobile phone by programming a name to be associated with the incoming (calling party) number. VCS and ICS have sustained only minimal market penetration. Despite its small success in the past, work is in progress that will provide greater value for mobile services, such as location-based services.

Work in Progress In order to provide value to service providers, WIN needed to support more advanced services. Prepaid wireless was the logical choice due to its marketplace success. The second phase of WIN, designed to support prepaid charging, has been approved for publication as IS-826, providing the ability for standardized IN-based wireless-prepaid services.

As a mobile IN protocol, IS-826 provides the ability to use WIN-based wireless prepaid while roaming, hence one of the major drawbacks of WIN vs. non-IN solutions: WIN-based solutions require both the home and serving wireless networks to support the required protocols and procedures to enable roaming. Although a major breakthrough in terms of support for a compelling service, WIN-based prepaid won't be ubiquitous until all participating service providers support IS-826.

Phase II also is represented by the IS-848 standard, which provides support for new mobile services such as Freephone, the ability to place toll-free calls (airtime and long distance). IS-848 also provides a new capability embodied by the position request (PosReq) message. The PosReq message provides the ability for an SCP to launch a request for mobile-position information to the HLR, allowing software logic in the SCP to use the data for mobile location-based services.

Built for the Future WIN Phase III standards are expected to be available in 2001 with the primary focus of standardizing protocols and procedures for support of commercial location-based services. These services include location-sensitive billing, location-based information and tracking services. Location-sensitive billing is the ability to charge the subscriber based on location. For example, a subscriber could receive a less expensive rate when calling from his home zone or a preferred rate when calling from a corporate campus. Standardized WIN Phase III capabilities will complement location-based service-architecture elements such as the mobile-positioning center, initially defined by PN-3890 for support of Phase II of wireless-emergency services, for various commercial-based services. The specific WIN Phase III capabilities will be embodied in PN-4818 for location-services architecture, PN-4746 for location-services authorization/privacy/security and PN-4747 for location-services enhancements. When available, these standards will define the protocols and procedures necessary for location-based services to integrate with the mobile network and other services.

Evolve to Data WIN is currently voice-centric, but its future will be largely determined by its ability to evolve to support data. As wireless-data applications driven by GPRS, EDGE and UMTS proliferate, there will be a need to manage the interaction between voice and data networks and call sessions. It's likely that WIN will need to evolve to support various multimedia applications that use traditional voice-network capabilities and IP-based technology. An example would be any service that uses WIN for call control and IP for access and transport.

Preliminary work is under way in the Internet Engineering Task Force (IETF) to define capabilities for hybrid IN + IP networks. One such hybrid is referred to by the IETF as PINT, for a combination of public-switched telephone network (PSTN) and Internet interworking. The motivation for PINT is to allow Internet subscribers to add traditional IN-related telephony functions so that conventional network capabilities and services are accessible and usable by Internet users for things such as call waiting during a wireless-Internet session.

Another hybrid technology approach is SPIRIT (services in the PSTN/IN requesting Internet services). SPIRIT's goal is to augment IN services with IP capabilities to make Internet-based content and applications accessible and usable by traditional network users. This technology will allow service logic to reside in any network node, including servers hosted on the Internet.

These initiatives are just the beginning of what will lead to the next-generation network. In fact, CTIA recently held a forum to obtain input from wireless companies to begin to define the goals and framework for WIN Phase IV. This stage of WIN evolution will begin to better leverage various aspects of IP technology and distributed network intelligence with the goal of enabling more advanced and flexible service options. Many of these services will involve m-commerce applications that bridge the Internet with mobile networks and leverage the key differentiator of mobility - location of the subscriber.

WIN Investment Historically, most wireless providers have viewed WIN as an expensive endeavor with little benefit and payoff. However, many are now beginning to see the potential power of WIN as an investment to improve network control and service-delivery capabilities. These improvements will be realized in improved performance of value-added services such as prepaid wireless and location-based services.

WIN provides roaming support for IN-based prepaid and reduced bearer facilities requirements as compared to other solutions, but perhaps more importantly, it pro-vides the ability to offer value-add-ed services to prepaid customers such as location-based charging.

WIN provides enhanced network capabilities in support of location-based services such as the ability to query network resources for location information. This will be especially important, as many of these services will be data-oriented and dependent on network signaling/intelligence for positioning.

WIN also will play a key role in leveraging core-network capabilities as increasingly more network elements rely on IP technology for access and transport. Despite the many efficiencies and benefits of IP-based networks, SS7 is expected to remain a required signaling protocol for core network architecture for many years. Although IP will help accelerate the trend toward distributed network intelligence, providers will continue to rely on SS7 and WIN for network control and service-logic control. In fact, WIN will provide the bridge between mobile networks and IP-based networks for emerging requirements such as PSTN to IP address mapping.

The Payoff Like any investment, there is a required gestation period. There is no immediate payoff. However, WIN offers the promise for long-term improvements in network efficiency and deployment of advanced services. It's important to remember that, by design, WIN capabilities are reusable. Triggers and messages can be used across a variety of different applications. Therefore, deployment of WIN capabilities provides more than just incremental improvement for existing services or even facilitation of new services. The greatest value will be realized when WIN-based-services deployment reaches a critical mass. This portfolio approach and long-term view of WIN is expected to justify investment in WIN for use well into the 21 superscript st century.