CAMEL 2 Standard Brings Enhanced Functionality to Prepaid

Prepaid wireless is driving the acceptance of CAMEL Phase 2 and Phase 3 as a standard implementation platform in GSM networks.

Prepaid wireless—once stigmatized as an application for poor credit risks who rarely traveled to other countries—is now burgeoning among traveling consumers and corporate users in Europe and Asia. Roaming services are becoming highly valued in countries with large prepaid bases, such as Spain, Portugal, and Italy.

“It’s difficult to estimate what percentage of users will take up roaming capabilities, but we think as much as 25 percent of the prepaid base may roam to other countries for business or pleasure, particularly in countries like Germany,” says Graham Cobb, director of intelligent networks and business development at Telcordia Technologies.

Real-time control to authorize call set-up, handle recharges, issue low-balance warnings and terminate calls when balances run out in real-time has not been feasible and cost-effective until now, according to Cobb, who points to ETSI’s Phase 2 of CAMEL (Customized Applications for Mobile network Enhanced Logic).

CAMEL Phase 2 allows real-time charging and call control with optimal routing of calls, facilitated by its global IN (intelligent network) standard. “This is a marked improvement over CAMEL 1, which required operators to route the call via their home networks,” says Cobb, who explains: “When UK mobile subscribers travelling in France made calls to a local restaurant, for instance, the call would be routed from France back to the UK and then back to France again.” Someone had to pay for the two International call legs—“either the subscriber through high tariffs or the operator who’d let it cut into their margin.”

Most operators are implementing CAMEL Phase II “as rapidly as they can” to avoid these sorts of hacks, as well as the costs of two international call legs, according to Cobb.

On an interim basis, operators have been using “USSD callback” methods for mitigating the costs of routing calls via home networks.

“Subscribers enter special codes into their phone, such as "#100#" in front of the phone number. The home network then would call the mobile back and, when answered, would then call the destination number,” says Cobb, adding that the process involves an awkward user interface. “Not to mention, subscribers dislike having to dial strange digit strings and then wait around for what could end up being delayed callbacks.”

Current users of CAMEL Phase 2 include Dutchtone, France Telecom Mobile, Mobistar and T-Mobil. Companies at the trial stage include Belgacom Mobile, BT Cellnet, E-Plus, Telia Mobil, and Viag Interkom.

Under CAMEL 2, there also is a separation of service control logic from routing logic as certain aspects of the network intelligence are removed from the switch and located in peripheral computer equipment. This means a move away from large switch centers to more distributed telecommunications systems.

Additionally, CAMEL 2 interacts with the specialized resource function (SRF)— a capability found in voice response units (VRU). Because CAMEL Phase 2 provides many additional INAP (intelligent network application part) capabilities to support SRF, the VRU can now play voice prompts during prepay account recharge and announce low balance warnings before or during a call. This is an improvement over CAMEL 1, where a call was simply terminated in progress when an account balance reached zero.

"All of this will expedite operators’ abilities to respond to new tariff plans, offer discounts and deploy loyalty schemes,” says Cobb, noting that Telcordia currently is working with Nokia to supply IN platforms and OSS software components to operators with its ISCP IN System.

Telcordia also is enhancing its ISCP platform, offering new functionality to support CAMEL 3 and Open Service Architecture principles adopted by the 3GPP (Third-generation Partnership Project), a consortia that develops technical specifications for 3G Mobile System based on GSM networks. “CAMEL 2 is not an endpoint; it’s just part of the evolution,” notes Cobb.

With CAMEL 3, Cobb expects there will be additional support for SMS roaming, as well as more complex billing capabilities for roaming on packet services such as GPRS, EDGE, and UMTS. “As long as we as an industry can overcome the key obstacles, CAMEL 2 and CAMEL 3 will take off,” predicts Cobb, noting that flexibility, openness and reliability will be critical factors. He believes the next step will be integration of prepaid and post-paid applications. “There are great products out there for the prepaid world, but how to incorporate with post-paid is important,” says Cobb. He adds that Telcordia is in discussions with billers in that area, but is not yet integrating its OSS products with traditional billers’ products. That, he expects, will be the next step, as mobile prepaid communications move to the forefront of mobile operators’ portfolios, as evidenced by such announcements as BT Cellnet’s launching of prepaid WAP services.