How does paging works in case of user is using VoWiFi?

Dear experts.

How does paging works in case of user is using Vo-WiFi?

Will it be through anchor LTE site or it will be via Wi-Fi?

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I think paging still comes on LTE.

User wakes up and then call established through WiFi.

Trying to find reference…

For a Call or SMS it will go over Wi-Fi.

IMS will send Call/SMS attempt to PGW.

For Wi-Fi users it will go through EPDG and Internet.


Yes, it seems to be right latest work flow.


I was trying to solve a customer complain where user faced a call fail issue since called party was using VoWiFi in poor Wi-Fi coverage.

IMS would try over CS after a certain period.

If user doesn’t reply and attempt goes to timeout.

Is there any timer at Core end?

It is configurable on Application Server.

Generally called cs-retry timer.

He can’t receive paging if he doesn’t register in wifi network, so sure it will be via WiFi.

If paging over CS retry gets successful, than call will establish on VoWiFi or will it switch to VoLTE?

Call will be established over cs network (2G/3G).

Our network is LTE only, no 2G or 3G.

No retry over LTE.

In the context of Voice over Wi-Fi (Vo-WiFi), paging works in a similar way to traditional cellular networks. However, there may be some differences in the underlying technology and implementation.
Vo-WiFi scenario.

  1. Registration: Before a user can receive calls or messages over Vo-WiFi, they need to register their device with the Vo-WiFi service provided by their network operator. This registration process establishes a connection between the user’s device and the operator’s Vo-WiFi infrastructure.

  2. Presence monitoring: Once registered, the Vo-WiFi infrastructure keeps track of the user’s presence or availability. It maintains the user’s location information, such as the IP address of their device, to enable incoming call delivery.

  3. Paging notification: When a call or message arrives for a user who is currently connected to the Vo-WiFi service, the Vo-WiFi infrastructure initiates a paging notification. This notification is typically sent to the user’s registered device or devices, indicating an incoming call or message.

  4. Device notification: Upon receiving the paging notification, the user’s device generates an alert, such as a ringtone or notification, to inform the user about the incoming call or message. The device establishes a connection with the Vo-WiFi infrastructure to handle the call or message.

  5. Call/message handling: Once the user’s device establishes a connection with the Vo-WiFi infrastructure, the call or message is routed to the device. The user can answer the call or view and respond to the message using the Vo-WiFi service.

Keep in mind that Vo-WiFi capabilities and features may evolve over time, so it’s essential to refer to the specific documentation or guidelines provided by your network operator or Vo-WiFi service provider for accurate and up-to-date information.

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