Objectives of WiFi Calling Implementation
Miatel’s primary customer base consists of corporate clients who have high demands for communication quality and operate in specific geographical conditions.
The main goal of implementing EPDG was to ensure stable voice communication in areas with limited access to certain mobile network frequencies. The use of VoLTE and VoWiFi allows for uninterrupted voice service even in locations where the operator’s networks are unstable or entirely unavailable.
In response to customer requests, the company initially introduced VoLTE, followed by WiFi Calling (VoWiFi). Both services share similar requirements for information systems and deployment processes, making the implementation of VoWiFi easier due to the experience gained with VoLTE.
Deployment Challenges
VAS Experts’ EPDG product was ready for operation by the end of 2023 and successfully met standards and specifications in laboratory testing.
Initially, integrating the solution into the operator’s infrastructure seemed straightforward. However, several challenges emerged during deployment.
The first minor issue arose when obtaining the EPDG service domain from GSMA. There was no response to the request for a long time, but after persistent communication, the domain was finally obtained. The security certificate did not function properly at first, revealing certain nuances that were resolved through joint efforts by the operator and the vendor. With only the SIM card configuration remaining, it seemed that connectivity would be established. However, at this stage, it was discovered that the phone did not recognize the new domain on the SIM card and refused to connect to the EPDG.
This led to an in-depth examination of the Android OS, manufacturer configurations, and even the phone’s modem. One RFC document stated that there are multiple ways to configure a carrier’s settings on a phone.
After months of research, it became clear that some phone models could be configured, but there was no universal approach—each phone model required a unique configuration method. As a result, the only viable approach, which most operators are slowly but surely adopting, is to work directly with phone manufacturers.
However, interacting with mobile device manufacturers proved to be a challenge. Large corporations like Xiaomi, Huawei, and Lenovo responded slowly to requests from smaller operators. The larger the operator, the higher the chances of receiving a prompt response, significantly accelerating the phone configuration process and the launch of WiFi Calling.
Results and Future Prospects
Despite the challenges encountered, all technical and organizational barriers were successfully overcome.
During the project:
- EPDG was integrated into the operator’s infrastructure.
- A knowledge base was created for future service scaling.
- The specifics of VoWiFi operation on virtual operator networks were studied.
Miatel continues to expand the list of supported devices and optimize the service. The implementation of WiFi Calling marks a significant milestone in the development of telecom infrastructure, providing additional capabilities for subscribers.