EPDG (Evolved Packet Data Gateway)

Solution for launching a new service in mobile operators' network — Wi-Fi Calling (VoWiFi)

Use cases

  • Roaming
  • Remote households (country houses, farms)
  • New neighborhoods
  • Large office buildings and shopping malls with rooms remote from windows
  • High-rise buildings and skyscrapers

For the operator

  • Solves the problems of insufficient coverage at the initial stage of VoLTE deployment
  • Reduces the cost of traffic for MVNOs
  • Enables cost-effective roaming services.

For the subscriber

Allows the subscriber to make and receive calls, send SMS to a cell phone number outside the network of his mobile operator via any available Wi-Fi network without installing additional applications and settings. Mobile network and Wi-Fi work together, good quality (HD) calls are switched between networks without the subscriber noticing.

People are increasingly relying on mobile devices. Poor cell phone service at home or work might force them to switch to another cell phone carrier. Wi-Fi Calling will help retain customers and improve the user experience.

How EPDG works

The ePDG is responsible for the interaction between the operator core (EPC) and untrusted non-3GPP networks that require secure access, such as Wi-Fi access networks, LTE metro and femtocells. The subscriber’s phone, through an embedded mechanism, organizes a secure ePDG connection transparent to the local Wi-Fi access point (AP), which authenticates the subscriber via SIM to the AAA server and organizes the interaction with the EPC.

Wi-Fi Calling is quickly launched on operators with VoLTE running and utilizes VoLTE-aware infrastructure.

epdg scheme

Contact us! We can help you create a roadmap for product implementation and select a configuration for your network.

EPDG Features

Extensible Authentication Protocol

Operator SIM based authentication – EAP AKA, EAP Based

Quality of Service

QoS based on information obtained through authorization, authentication and accounting (AAA)


Full support for IPSec/IKEv2 based interface between UEs WLAN (wireless LAN) and ePDG. An IPSec tunnel is created from the user equipment for each packet data network (PDN) session and protects both the user equipment and the wireless packet network core

Increased productivity

IPSec is extremely resource-intensive, which can impact user experience and kernel performance if run by a general-purpose platform. The ePDG combines support for high-load service interfaces with low power consumption. In addition, encryption and decryption will have minimal impact on latency

Voice continuity

Phones freely switch the signal between Wi-Fi and LTE eNodeBs to ensure uninterrupted voice transmission (handover)

High quality voice communication

VoWiFi and VoLTE operate on the same core network and use the same HD codecs to provide subscribers with high-quality audio/video services

Wi-Fi network HotSpot selection control

Operator can set the option to connect to specific Wi-Fi HotSpots or leave the choice up to the subscriber

Support for emergency services

Although the call is not over the cellular network, the subscriber still has the option to contact local emergency medical services, police and other emergency services like 911

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