All operators have launched VoWiFi: how this new technology transforms communication during outages.

<At the end of 2024, all mobile operators in Ukraine launched the VoWiFi technology, which enables calls to be made over a Wi-Fi network. Its key feature is significantly improved call quality and stability, particularly when the mobile network is congested or when the signal is weak.

In the context of Ukraine, VoWiFi has found additional practical applications. During power outages, when the load on mobile networks sharply increases and call quality deteriorates, Wi-Fi calls can become a reliable alternative.

lifecell was the first among Ukrainian operators to implement VoWiFi. Within two years, all telecom providers have offered this service, ensuring its availability throughout Ukraine. For telecom companies, this represents an opportunity to expand network coverage, while for consumers, it provides an additional means of communication, especially during winter power outages.

We explain what VoWiFi is, how this technology works, and what is needed for its use.

What are VoWiFi and VoLTE technologies

VoWiFi (Voice over Wi-Fi) is a technology that allows users to make calls and send SMS via a Wi-Fi network, even when mobile signal is weak or completely absent.

VoWiFi is somewhat similar to VoIP services like Skype or WhatsApp, as both transmit voice using the IP protocol. The difference is that VoWiFi is directly integrated with the operator's mobile network. For the user, it appears as a regular call or message, but technically the process is different.

During a call, the user's voice is converted into digital data packets (similar to VoIP) and transmitted over the internet connection to the mobile operator's network. The call is then routed to the recipient via the cellular network. The conditions for using this technology for international calls depend on the specific service provider.

VoWiFi works in tandem with VoLTE (Voice over LTE), which allows voice calls to be made over the 4G LTE network, unlike traditional calls that utilize 2G or 3G networks. This combination has additional advantages. For instance, a call will not drop even when transitioning from a Wi-Fi zone to an LTE coverage area or vice versa, ensuring stable connectivity.

VoWiFi and VoLTE significantly enhance call quality and allow users to make calls while simultaneously using the internet. According to the press service of Vodafone, VoLTE enables users to make or receive calls while remaining online: using navigation, searching for information, or receiving messages.

These technologies not only eliminate noise and interference during calls but also effectively relieve network congestion. VoLTE transmits voice calls over 4G, reducing the load on 2G/3G networks, which is beneficial for operators. VoWiFi, on the other hand, expands network coverage through Wi-Fi, providing connectivity in areas with weak or absent mobile signals.

What is the purpose of VoWiFi

The main functions of VoWiFi and VoLTE technologies are to improve call quality and allow users to make calls while using the internet simultaneously. According to Vodafone's press service, VoLTE enables users to receive calls while staying online: using navigation, searching for information, receiving messages, or scheduling meetings in a calendar.

These technologies not only eliminate noise and interference during conversations but also help optimize network performance. "VoLTE transmits voice calls over 4G, reducing load on 2G/3G networks, which is particularly advantageous for operators," noted Vodafone.

VoWiFi, in turn, expands network coverage via Wi-Fi, providing quality connectivity even in areas with poor or nonexistent mobile signal. In the context of war and frequent power outages, VoWiFi becomes an effective alternative that can help subscribers stay connected even with weak or unstable signals.

The Ukrainian telecom infrastructure is designed for 80% of traffic to go through home internet. However, during blackouts, subscribers switch to mobile internet, which increases the load on base stations (BS) and significantly deteriorates call quality.

In cases of prolonged outages, even base stations may cease operations. To avoid this, the National Center for Operational and Technical Management of Telecommunications Networks (NCU) updated requirements for mobile operators on July 15.

Now operators are required to ensure the autonomous operation of base stations for 10 hours. By October 1, 2024, 60% of BS must meet this standard, and by the end of January 2025, 100%. Despite significant investments by telecom companies in energy independence for networks, it is impossible to fully comply with these requirements by the specified deadlines.

In such conditions, VoWiFi can become an effective alternative to stay connected and reduce the load on the mobile network. Especially considering that recently the Ministry of Digital Transformation initiated a campaign to transition the population to the xPON technology, which allows using home internet for up to 72 hours during power outages. The PON (Passive Optical Network) technology provides high-speed and energy-efficient access to the internet without additional electrical equipment.

"If the mobile network signal is weak due to a power outage, VoWiFi can provide stable connectivity as long as there is backup power for Wi-Fi and access to the internet," explained Kyivstar.

Thus, a user with stable access to Wi-Fi, even during outages, can remain connected, particularly for calls to emergency services. Additionally, VoWiFi will be useful in shelters during air raid alerts, where mobile network signals are typically poor.

Lifecell also notes certain technical limitations: after activating airplane mode or losing access to the mobile network, including national roaming, calls via VoWiFi will only remain available for 10 minutes. After that, they will be unavailable until the mobile network connection with lifecell is restored.

Who provides the VoWiFi service and how

The mobile operator lifecell was the first in Ukraine to implement VoWiFi technology. In September 2022, the company announced the launch of this service for its subscribers. Lifecell notes that VoLTE and VoWiFi are available to most users, provided that their smartphones support these technologies.

For a long time, Kyivstar only offered VoLTE, which, according to the company, is used by over 5 million subscribers. However, on December 11, 2024, the largest operator in Ukraine also launched VoWiFi.

The company reported that to ensure stable network operation, access to the technology for fixed internet users will be opened gradually. Initially, VoWiFi will be available for subscribers using fixed internet from Kyivstar, and within the upcoming weeks, it will also be accessible to customers of other providers in Ukraine.

"If a subscriber is already using VoLTE from Kyivstar, there is no need to additionally connect VoWiFi. The service activates automatically after installing the necessary software on the device. For subscribers who are not yet using VoLTE but have devices that support VoWiFi on the Kyivstar network, access can be enabled by contacting the operator," the company explained.

In early December 2023, Vodafone began testing VoLTE and VoWiFi. Currently, Wi-Fi calls are available throughout Ukraine, and LTE calls are operational in cities such as Kyiv (particularly in the metro), Dnipro, Uzhhorod, Odesa, Chernivtsi, Poltava, Ivano-Frankivsk, Kropyvnytskyi, Mykolaiv, Lviv (city center), Chernihiv, Kovel, Lutsk, Kolomyia, Oleksandriia, Bukovel resort, Kalush, Chornomorsk, Myrhorod, Lubny, and Priluky. Vodafone plans to gradually expand VoLTE coverage to all of Ukraine within the year.

Additionally, Kyivstar, Vodafone, and lifecell assured that calls made using VoWiFi are charged as regular voice calls within the operators' networks, without any additional fees. The companies also added that currently, the technology does not operate in roaming or with VPN usage.

What are the requirements for using VoWiFi

To make calls over a Wi-Fi network, first ensure that your smartphone and its software are compatible with VoWiFi technology. It's advisable to contact your operator and check if this service is activated for your number. Using a modern USIM card, which allows operation in LTE networks and supports VoWiFi, is mandatory.

You should also check if your smartphone is compatible with this technology within the mobile operator's network. To activate the feature, VoWiFi must be enabled in the phone settings, and the software should be updated to the latest version. This will ensure stable connectivity even in areas with poor mobile coverage.

Generally, VoWiFi technology is available primarily on modern smartphones with the