VoWIFI: solving connectivity challenges with your mobile phone

Author: Nico Maes, Product Manager Mobile

With the current insulation norms but also in industrialized environments indoor coverage is a pain point for users of mobile phones. As mobile networks and WiFi capabilities continue to advance, VoWifFi presents a compelling solution that offers enhanced connectivity and improved voice communication quality. We introduced VoWiFi in September 2023 together with the introduction of VoLTE. Regarding VoLTE see also “VoLTE: Revolutionizing Communication on your mobile phone”.

Understanding VoWiFi

Voice over WiFi, often referred to as VoWiFi or WiFi Calling, is a technology that enables users to make and receive voice calls using a WiFi network rather than traditional cellular networks. This means that as long as a device is connected to a stable WiFi network, it can transmit voice data packets over the internet to establish a call. VoWiFi technology, is an extension of Voice over IP (VoIP) technology and works by converting analog voice signals into digital packets, which are then transmitted over the internet to the recipient's device. This technology is particularly advantageous in areas with poor cellular coverage but strong WiFi signals, as it provides a reliable alternative for making calls.

Benefits of VoWiFi

Enhanced Call Quality
VoWiFi is known for providing superior call quality compared to traditional cellular networks, especially in areas with weak cellular signals. By utilizing the high bandwidth of WiFi networks, voice calls are less dropped, interfered, and distorted, resulting in clear and crisp conversations.
Extended Coverage
VoWiFi allows users to make and receive calls in places with limited or no cellular coverage, such as basements, underground spaces, and remote locations. As long as there is a stable WiFi connection, users can stay connected regardless of their physical location.
Seamless Handover
One of the remarkable features of VoWiFi is its ability to seamlessly hand over calls between WiFi and cellular networks without interruption. For instance, if a call is initiated over WiFi and the user moves out of WiFi range, the call can smoothly transition to the cellular network without dropping, however it should be taken into account that it is the device that is in charge, meaning if you move out of WiFi coverage it can be that the device keeps connected on WiFi too long and that you experience a short hiccup in your call, the call wont be dropped but it can happen that for a few seconds you won’t hear anything.

Cost Savings
VoWiFi leads to cost savings for the network providers. By offloading voice traffic to WiFi networks, mobile operators can reduce the load on their cellular networks, potentially resulting in lower operational costs.
Battery Efficiency
VoWiFi can help conserve battery life. When in an area with strong WiFi signals, the device uses less power to transmit data compared to when it's struggling to maintain a cellular connection in a weak signal area.
Integrated Experience
VoWiFi seamlessly integrates with existing contact lists, call logs, and other native phone functions. Users do not need to install separate applications or create new accounts to use this service.

Voice over WiFi (VoWiFi) works on the internet connectivity provided by WiFi networks to transmit voice data packets, allowing users to make and receive voice calls using their devices. This technology involves a series of steps that convert analog voice signals into digital data and then transmit them over the WiFi network.

This is a simplified breakdown of how VoWIFI works:

Voice Signal Conversion:
When a user initiates a call on their device, their voice is captured as an analog signal through the microphone. This analog signal needs to be converted into digital data that can be transmitted over the internet.
Digitization:
The analog voice signal is converted into digital format through a process called analog-to-digital conversion. This involves sampling the analog signal at regular intervals and assigning digital values to those samples. The resulting digital data represents the voice signal in a form that can be easily transmitted as packets of data.
Packetization:
The digitized voice data is divided into small packets. Each packet contains a portion of the voice data along with additional information like source and destination addresses. These packets are then ready for transmission.
Internet Transmission:
The packets of voice data are sent over the WiFi network as IP (Internet Protocol) packets. The device uses the existing WiFi connection to establish a link to the internet, and the packets are routed through the WiFi router to reach their destination.
Reception and Reassembly:
On the receiving end, the digital voice packets are received by the recipient's device. The device reassembles the packets in the correct order based on the information included in each packet. This process is called packet reassembly.
Digital-to-Analog Conversion:
Once the packets are reassembled, the recipient's device converts the digital data back into an analog signal through a process called digital-to-analog conversion. This analog signal is then played through the device's speaker, allowing the recipient to hear the voice of the caller.

VoWiFi is generally considered to be secure, especially when implemented and managed by reputable service providers. However, like any technology that involves transmitting data over networks, there are certain security considerations to be aware of.

Here's a closer look at the security aspects of VoWiFi:

Encryption:
VoWiFi implementations use encryption to protect the voice data packets as they are transmitted over the WiFi network. Encryption ensures that the data is encoded in such a way that only authorized parties with the appropriate decryption keys can access and understand the information. This prevents unauthorized eavesdropping and interception of voice calls.

Secure Protocols:
VoWiFi calls typically use secure communication protocols, such as Transport Layer Security (TLS) or Secure Real-time Transport Protocol (SRTP), to establish encrypted connections between devices and the service provider's servers. These protocols ensure that data is transmitted securely and cannot be easily intercepted or tampered with.

Netwerk Security:
The security of VoWiFi calls also relies on the overall security of the WiFi network being used. If the WiFi network is not properly secured with strong encryption (such as WPA2 or WPA3) and a strong password, there is a potential risk of unauthorized access to the network and the data transmitted over it.

Device Security:
The security of the user's device itself is also crucial. If the device has malware or security vulnerabilities, it could potentially compromise the security of VoWiFi calls. Keeping devices updated with the latest security patches and using strong security practices (such as using strong passwords and avoiding public WiFi networks for sensitive activities) can help mitigate these risks.

Potential Risks:
While VoWiFi is generally secure, there are potential risks to be aware of. If the WiFi network is unsecured or compromised, there is a risk of unauthorized access. Additionally, like any technology, there is always a possibility of vulnerabilities being discovered and exploited. However, reputable service providers and device manufacturers actively work to identify and address such vulnerabilities through regular updates and patches.

Conclusion

VoWiFi has emerged as a key enabler in solving connectivity challenges with mobile phones. Its ability to enhance call quality, extend coverage, and seamlessly integrate with existing services positions it as a solution that is not only practical but also essential in today's interconnected world. As we look ahead, the continued refinement of VoWiFi technology promises to further enrich our communication experiences, providing reliable and efficient connectivity wherever we go and wherever we go.

Glossary of used terminology:

VoWIFI (Voice over WiFi):
A technology that lets you make calls using WiFi instead of cell networks

VoLTE (Voice over LTE):
Making high-quality voice calls on 4G networks.

Connectivity Challenges:
Issues with staying connected on phones.

Indoor Coverage:
Signal strength inside buildings.

Analog Voice Signals:
Original voice converted to electrical signals.

Digital Data Packets:
Small data pieces for sending voice.

Bandwidth:
Data capacity of a connection.

Seamless Handover:
Switching networks without call drops.

Internet Protocol (IP) Packets:
Data chunks sent over the net.

Encryption:
Making data unreadable for security.

Transport Layer Security (TLS):
Secure communication protocol.

Secure Real-time Transport Protocol (SRTP):
Securing real-time data.

WPA2/WPA3:
WiFi security protocols.

Malware:
Harmful software.

Vulnerabilities:
Weaknesses in systems.

Security Patches:
Updates for fixing security issues.