by Brian Moore, Director - Wireless Marketing
TSI Telecommunication Services Inc.
USA

Wireless 3G systems are beginning to emerge, and the resulting advanced applications that require high data speeds are likely to revolutionize the wireless world - much more dramatically than digital technology did just a few short years ago. The Yankee Group predicts that 3G will account for 11 percent of the global wireless subscriber base by 2005, and some hail 3G as the panacea to many of the wireless world's current interoperability problems. Unfortunately, the reality is that many of today's current interoperability challenges will remain, as different operators and manufacturers interpret standards differently and continue to integrate new technology with legacy networks.

This is particularly the case with international roaming - even as the opportunities for roaming continue to grow. In fact, international travel grew 7.1 percent between 1997 and 1999, and an estimated 522 million international airline trips were scheduled in the year 2000. This growth means additional revenue opportunities for wireless operators savvy enough to support international roaming and extend their services beyond their own borders.

A case study on individuals traveling between the Asia-Pacific and North American markets alone illustrates international roaming's huge potential to increase wireless airtime revenue. In 2000, an estimated 24.6 million individuals traveled between the Asia-Pacific region and North America. Assume that an estimated 20 percent of these individuals had wireless phones (i.e., the first class and business travelers). If you assume the average trip length was five days, during which each individual made five three-minute calls per day at 50 cents per minute, total airtime revenue realized from this international roaming activity would be approximately $185.6 million.

Braving the Elements: The Fundamentals of International Roaming

To realize the benefit from such revenue gains, wireless operators must overcome the challenges associated with international and inter-standard roaming. This requires bridging the gap between different numbering schemes, different billing and signaling systems, and different network elements. Operators must deal with issues that range from managing roaming agreements and network interoperability to settling roaming debts, managing fraud and training their customer care departments to troubleshoot roaming-related problems. Fortunately for wireless operators, they can turn to TSI for an end-to-end solution that addresses each element of establishing a seamless international roaming service for customers.

Establishing Roaming Agreements

The first step in establishing international roaming is determining where - and with which operators - a service provider would like to enable its subscribers to roam. Querying customers to determine their top international travel destinations goes a long way toward establishing location priorities. But then begins the process of contacting the various operators in that region to negotiate pricing and other details - unless operators turn to a solution such as TSI's Universal Roaming Services Alliance. The alliance allows operators to quickly and easily establish roaming agreements with multiple operators using a standard set of terms, conditions and rates. The alliance does the work for operators, researching relevant operators and working out roaming terms- but also leaving them the option to create their own roaming terms if they so desire.

Non-standardized Air Interfaces

Although air interface standards continue to represent a barrier to roaming, the good news is that more than a dozen handset manufacturers now make dual- or tri-mode phones, many of which operate in several different countries. However, the ability of handsets to switch air interfaces is only part of the solution. Different air interfaces affect other network elements such as signaling, billing and even switching standards, as discussed below.

Non-interoperable Network Elements

International roaming is based on the exchange of signaling messages, billing records and other information. Operators need to ensure that their networks - and the switches and databases connected by them - are compatible with their roaming partners, or they will not be able to exchange information. In the international roaming arena, ensuring compatible connections is especially difficult, requiring protocol conversions such as those between the ANSI SS7 standard used in the Americas and the ITU C7 standard used in Europe and other parts of the world. Various versions of ITU C7 and ANSI SS7 must be integrated through a centralized point providing the necessary protocol conversions. A centralized interface such as TSI's signaling solution eliminates the need for wireless operators to build and operate their own network connections and the interoperability testing of these connections with each roaming partner.

TSI's international signaling gateway ensures this interoperability, providing operators with basic network infrastructures (SS7, X.25, frame relay, Internet Protocol) as well as unique, hybrid solutions that can reduce costs and increase system reliability. For instance, TSI developed an SS7 over frame relay signaling solution for four CDMA-based wireless operators in the Asia-Pacific area. This unique network solution not only was more cost-effective for the operators than using straight SS7 links; it also gave the operators the ability to support multiple applications across a single IP transport backbone.

Switching Systems

When it comes to exchanging roaming data, even switches based on the same standard can be incompatible since each switch manufacturer may interpret the standard slightly differently. Again, a centralized point for international signaling can resolve these incompatibility issues and help ensure that a subscriber's usage features follow that individual when roaming in another market. TSI works with each operator to help identify specific issues and adapt a solution to meet the operator's needs.

Signaling and Numbering Issues

Without signaling, or the transfer of the information that controls wireless communications, there would be no roaming. Signaling is particularly difficult between Global System for Mobile (GSM) communications networks, which are based on the signaling standard GSM Map, and IS-41 systems such as Advanced Mobile Phone Service (AMPS), narrowband AMPS, Time Division Multiple Access (TDMA) and CDMA. Interoperability among these revisions can be provided through a centralized call processor-based Service Control Point (SCP) such as TSI's Signaling Solution.

One difficult aspect of connecting different signaling systems is the management of point codes. Point codes are addresses used to identify switches and to route messages through the network. Within North America, which uses the ANSI standard for SS7, the allocation of point codes has been coordinated so that each switch is associated with a unique point code. However, countries outside of North America, which use the ITU version of SS7, each have their own domain of addresses that are independent of other countries. Therefore, a specific ITU point code could be used in multiple domains, thus causing confusion when routing messages. By using a centralized signaling SCP such as TSI's to route ANSI-41 messages, operators can use only one point code for all line ranges, greatly simplifying the administration of the various line range-to-point code relationships.

Mobile System Identifier (MSID or SID) codes can also present numbering conflicts between countries. Wireless systems use five-digit SID codes to uniquely identify each operator's network and market. SID ranges are allocated internationally by the International Forum on AMPS Standards (IFAST) and in North America by CIBERNET. Since international coordination of SID assignments is relatively recent, some SIDs are in use by operators in more than one country. An operator with a large base of embedded non-IFAST SIDs must either find a solution to potential SID conflict issues or consider reprovisioning its SIDs and re-programming subscriber handsets.

One TSI customer in Latin America, recently faced this dilemma when it wanted to establish roaming from its home country of Brazil into North America. The operator's SID conflicted with a SID used by a major wireless operator in New York. Using TSI's Signaling Solution, the Latin American operator now routes ANSI-41 signaling messages through TSI's call processor, which maps the Latin American in-country SID to an IFAST SID. The New York operator then interprets this SID as a North American compliant, non-conflicting SID. When the signal comes back from the roaming market, it is recognized as the Latin American operator's SID. Problem solved.

In the numbering arena, differing international standards are also an issue. Given the variety of telephone numbering schemes throughout the world, countries have adopted different dialing methods to place international calls. Some switches using ANSI-41 standards are unable to determine if a Temporary Location Directory Number (TLDN) received from a serving switch is formatted as a national or international number. This renders the switch helpless to determine how to use the received TLDN to deliver a call to a subscriber roaming internationally. TSI's centralized call processor determines the necessary manipulation of the received TLDN to build a digit stream that routes the call successfully between the specific international locations.

Data Clearing, Settlement and Reporting

In order to receive the financial rewards that international roaming can deliver, an operator must have an efficient process in place for the exchange of roaming billing records with roaming partners. Without a clearinghouse such as TSI to serve as the Authorized Receipt Point (ARP) for the operator, this process can be overwhelming. A clearinghouse simplifies the complex record exchanges among operators with different switch record formats, billing record formats and signaling and numbering standards. In addition, the clearinghouse edits and validates all roaming records and provides financial settlement information, exchanging funds between operators via a major banking institution. TSI's clearinghouse services also provide operators with a unique benefit: The ACCESSibility Internet-based roaming revenue reporting system provides immediate online access to reports containing detailed revenue and usage data.

Customer Care

Good customer care has always been a big challenge in international roaming, as local operators are often hindered by a lack of information and language barriers. TSI's advanced online customer management tool solves this problem by giving operators near real-time visibility of a subscriber's roaming activity, including the display of IS-41 messages, so that operators always know where their customers are and are aware of potential problems - giving the home operator control of customer service as their customers roam overseas.

Fraud Management

Fraud places a serious financial burden on all operators. In fact, IDC expects wireless operators in the United States alone to lose in excess of $57 million a day to fraud by 2003. Fraud also poses a huge inconvenience to customers. Many operators fear that international roaming will increase these losses, but this does not have to be the case. TSI's turnkey fraud profiler solution provides state-of-the-art, integrated fraud protection services that can help minimize this problem.

Comprehensive roaming solutions such as those offered by TSI will continue to help operators overcome the challenges involved with international roaming, providing operators around the globe with an easy way to tap into potentially millions of dollars in roaming revenue while also offering their customers a valued service.