The growing reliance on connectivity and the need for constant communication has given rise to new technologies in the telecom space. Voice over Wi-Fi, or VoWi-Fi, is one such technology that is making telephonic conversations smooth and uninterrupted. VoWi-Fi delivers commercial telephone services through voice over IP (VoIP) technology on mobile devices linked to Wi-Fi.

In contrast, voice over LTE (VoLTE) utilises licensed spectrum of a mobile network operator, that is, 4G LTE, to transport packetised voice. VoLTE is a technological step up over regular, 2G-based calls. Voice calls are now made using 4G or LTE networks and not 2G networks. Thus, the user is able to make high quality voice calls and also use the internet while on the phone.

While VoLTE requires a mobile network connection, VoWi-Fi allows calls over Wi-Fi. In fact, Wi-Fi calling is being introduced in areas where cellular networks are not strong. It uses a high speed internet connection, available via broadband, to make high definition (HD) voice calls. This is not much different from a voice call using WhatsApp or any other over-the-top messaging platform, but here the call is from one number to another, and not using an app.

Key benefits

  • Scalable: VoWi-Fi allows mobile network operators to swiftly and efficiently increase their service range and coverage regions without constructing costly radio access networks, investing in additional spectrum, or entering into complex roaming agreements. In addition to offloading congested cellular networks, mobile operators can rely on Wi-Fi to reduce congestion.
  • In-building connectivity: VoWi-Fi is a simple solution for network operators and enterprises to provide in-building wireless voice services. It allows users to stay connected even when there is no cellular connection. VoWi-Fi enables customers to make and receive calls consistently even when they are indoors, without the need to install additional equipment or upgrade their smartphones.
  • Security: In contrast to weak cryptographic components or weak user/password credentials, VoWi-Fi leverages SIM security methods to verify and safeguard subscriber communications. Similar security requirements can be applied to circuit switched, packet switched and Wi-Fi calls as well.
  • Cost savings: VoWi-Fi generates major cost savings while enabling new IP services such as video calling, multi-device support, multimedia sharing across mobile broadband devices. It lowers the attrition or churn rate, thus saving operator revenues. It has also reduced the cost of building LTE base stations and femtocells for mobile operators. Since VoWi-Fi leverages the investment made in the Wi-Fi network infrastructure by enterprises, incremental expenditures are typically minimal.
  • Compatibility: The service is global and operates invisibly over any Wi-Fi network as long as the user has a device that supports VoWi-Fi. It is not unique to any operator and may save users from paying roaming charges when travelling overseas.

Current status in India

Bharti Airtel introduced VoWi-Fi in December 2019 and acquired 1 million subscribers within a month of its introduction. Known as “Airtel Wi-Fi calling”, the service is accessible in all 22 telecom circles and is supported by over 300 devices.

Reliance Jio announced the launch of voice and video calling over Wi-Fi in January 2020. The only prerequisite for using Jio’s Wi-Fi calling feature is a compatible handset that supports Wi-Fi calling with a Jio SIM and an active Jio tariff plan. To expand its reach, the telco has made the service available throughout the country with no additional charge. All Wi-Fi calls to Indian numbers will be free of cost, regardless of the location of users within India.

Vodafone Idea Limited is currently providing VoWi-Fi services in four circles. It has extended the VoWi-Fi functionality to only nine devices as part of the expansion, seven from Xiaomi and two from OnePlus.

Bharat Sanchar Nigam Limited (BSNL), too, has come out with plans to offer its Wi-Fi calling services through its Wings app. BSNL customers will be charged a one-time registration fee of Rs 1,099, after which they can make free calls to any network in India for one year.