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Wi-Fi calling put into commercial operation

Standard mobile calling and sending SMS and MMS over a Wi-Fi network. Calls switched smoothly between Wi-Fi and the LTE network. The service is free of charge; calls and messages are billed according to customers’ plans.

T-Mobile is the first operator in the Czech Republic to have commercially launched Wi-Fi calling, a service enabling standard mobile calling and sending of text and multimedia messages over a Wi-Fi network. The service is now available to corporate customers. Wi-Fi calling is currently supported by the Samsung Galaxy S6 edge; in cooperation with handset manufacturers, the operator is working to expand its portfolio with other devices supporting this technology.

“Following successful internal operation, Wi-Fi calling is now being launched also for our customers,” says Milan Hába, Vice President Technology & Business Innovations at T-Mobile, adding: “Each Wi-Fi hotspot in the Czech Republic can potentially become our transmitter.”

The service, which is now commercially available to corporate customers, is free of charge and calls and messages are billed in the standard manner according to customers’ plans. No installation is needed if customers want to use the service; all that is required is to switch it on in the given handset’s menu (provided that the firmware is up to date and the handset was purchased in the T-Mobile distribution network). For technical reasons, Wi-Fi calling will become available to residential customers later, in the first half of 2016.

Wi-Fi calling is based on the Voice over Wi-Fi (VoWi-Fi) technology, which enables making standard mobile calls and sending text and multimedia messages over a Wi-Fi network. With this technology, users can make calls and send messages from their numbers in the same way as they do in a mobile network. The service is valuable particularly in places where there may be problems with the strength or quality of the mobile signal, such as basement-level restaurants, bars, dance clubs and steel structures used as production facilities and warehouses.

The service offers superior quality voice transmission with suppression of ambient noise and fast call connection (similarly as VoLTE). If a Wi-Fi network is available in a particular place, the phone will use it automatically. When customers leave a place with Wi-Fi coverage, calls switch smoothly to the LTE network, similarly as in the case of VoLTE calls. The same principle also applies when switching from LTE to Wi-Fi. This functionality has to date been put into operation by only a few operators worldwide.