VoWiFi in Xiaomi Redmi: how calls over Wi-Fi save communication and improve quality

Have you ever noticed that in the basement of your home or office, mobile communication disappears and VoWiFi suddenly appears in the status bar of Xiaomi Redmi? It's no coincidence that your smartphone automatically switched to Wi-Fi calls so you do not get out of touch. Voice over Wi-Fi (VoWiFi) technology has been integrated into Xiaomi firmware for several years, but many users still do not know how to use it or even what it is.

In this article, we’ll explore why VoWiFi in Redmi is not just a tick feature, but a real tool for saving traffic and improving connectivity. You’ll learn how the technology works at the physical level, which Xiaomi models support it (spoiler: not all!), and why carriers sometimes block this feature.

What is VoWiFi and how it works in Xiaomi smartphones

VoWiFi (Voice over Wi-Fi) is a technology that allows you to make voice calls and send messages. SMS Unlike messaging apps like WhatsApp or Telegram, where calls are made over the Internet but require a separate application, VoWiFi is integrated at the operating system level and works with a regular phone number.

How does it work technically? When you call VoWiFi, your Xiaomi Redmi:

• 📶 Checks the quality of cellular communication. If the signal is weak (for example, in the subway or country house), the smartphone automatically switches to Wi-Fi.
• 🔄 Establishes a secure connection to your mobile operator’s servers via the protocol IMS (IP Multimedia Subsystem).
• 📞 Routing a call over the internet, but displaying it as a regular call in a log.
• 🔒 Encrypts data according to the standard SRTP (Secure Real-Time Transport Protocol to prevent interception.

It's important to understand that VoWiFi is not the same as Wi-Fi Calling in instant messengers.

VoWiFi in Xiaomi Redmi supports not only voice transmission, but also voice transmission. SMS — This means that even in a non-cellular zone, you can send regular texts over Wi-Fi.

Xiaomi Redmi models support VoWiFi

Not all Xiaomi smartphones can work with VoWiFi – it all depends on hardware support and version MIUI. Here are the key conditions:

• 📱 Processor: should support IMS (IP These are most Qualcomm Snapdragon chips (600 series and above) and some MediaTek chips (Helio). G85 newer).
• 🔄 Version. MIUI: VoWiFi has appeared in the MIUI 11, It only works consistently with MIUI 12+. On the Redmi Note. 8/9 You may need to update to the latest firmware.
• 📡 Operator support: Even if your smartphone supports VoWiFi, your mobile operator can block it (more on this below).

List of Xiaomi Redmi models that are guaranteed to support VoWiFi (subject to the current firmware):

⚠️ Note: If your model is on the list but VoWiFi is not working, check the version. MIUI In Settings → It's about the phone. It takes a stable job. MIUI 12.5 or later: VoWiFi may not work on custom firmware (e.g. LineageOS.

How to turn on VoWiFi on Xiaomi Redmi: step-by-step instructions

If your smartphone and carrier support VoWiFi, you can turn it on in 2 minutes.

1. Open Settings and go to the SIM Cards and Mobile Networks section.
2. Choose yours. SIM-card (if two of them).
3. Tap on Wi-Fi calls (or VoWiFi in some versions) MIUI).
4. Switch the slider to the position on.
5. Confirm the activation if a request from the operator appears.

If Wi-Fi Calls are not on the menu, try these methods:

Update MIUI last-minute|Reboot the phone|Check the support of the operator (list below)|Enable VoLTE (without it, VoWiFi does not work)|Reset network settings in Settings → System system → Resetting settings → Resetting mobile network settings

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Video Instructions: If you are hard to read, check out the official video from Xiaomi (available on YouTube for “VoWiFi Xiaomi Redmi”).

⚠️ Note: Some models (e.g. Redmi Note 8 Pro) may lose mobile internet after VoWiFi is turned on. This is a firmware bug, so rebooting or rolling back to an older version will help. MIUI.

Which operators in Russia and CIS support VoWiFi

VoWiFi technology depends not only on the smartphone, but also on the mobile operator, and in Russia and CIS countries the situation is as follows:

In Ukraine, VoWiFi supports:

• 🇺🇦 Kyivstar – on all tariffs from 2022.
• 🇺🇦 Vodafone UA — Only for VoLTE subscribers.
• 🇺🇦 Lifecell - in test mode (unstable).

In Kazakhstan and Belarus, VoWiFi is available from most operators, but may require separate activation via the Internet. USSD-teams (e.g. *100# for A1 in Belarus).

⚠️ Note: If you use a virtual carrier (such as Tinkoff Mobile or SberMobile), VoWiFi will probably not work – these carriers do not have their own infrastructure for the use of mobile devices. IMS.

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Before traveling abroad, check if your local carrier supports VoWiFi. In Turkey, VoWiFi is available for Turkcell and Vodafone, for example. TR, and in Thailand, AIS And TrueMove, which will help you avoid roaming.

Advantages and Disadvantages of VoWiFi in Xiaomi Redmi

VoWiFi is not a perfect technology. It has both obvious advantages and hidden pitfalls. Let's get this straight.

✅ The Pros of VoWiFi

• 📶 Stable communications in the area of poor coverage. 1-2 network sticks, but there is Wi-Fi, calls will not stop.
• 💰 Traffic savings: VoWiFi calls don’t waste mobile internet (unlike instant messengers).
• 🔊 Better sound quality. With good Wi-Fi, voice is transmitted in a format. HD Voice (broadband audio codec).
• 📱 Smooth transition between Wi-Fi and cellular network, and if you step out of Wi-Fi coverage, the call won't be interrupted, the phone will automatically switch to the mobile phone. 4G.

❌ Cons of VoWiFi

• 🔋 Increased battery consumption: constant operation of the Wi-Fi module and IMS increases energy consumption by 5-10%.
• 🛑 Dependence on Wi-Fi quality: If the router "lags" or too far, calls will be interrupted.
• 🔒 Problems with corporate networks: VoWiFi is blocked by firewalls in some offices.
• 📵 It doesn't work in "On the plane" mode. Even if you turn on Wi-Fi, VoWiFi will turn off (requires separate permission from the operator).

Comparison with alternatives:

| Calling method. | Quality of communication | Traffic. | Number displayed | It works without the internet. |

|---------------------|----------------|--------|--------------------|-----------------------|

| VoWiFi | ⭐⭐⭐⭐ | No. | Yes. | No. |

| VoLTE | ⭐⭐⭐⭐ | No. | Yes. | Yes. |

| Messengers | ⭐⭐⭐ | Yes. | No. | No. |

| Regular calls. | ⭐⭐ | No. | Yes. | Yes. |

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VoWiFi is the best choice for home use, where Wi-Fi is stable and cellular communication is weak. For the street, it is better to leave VoLTE or regular calls.

Typical VoWiFi Problems and How to Solve Them

Even if it’s set up correctly, Xiaomi Redmi users sometimes encounter bugs, and here are the most common problems and solutions:

🔴 VoWiFi is not turned on (gray slider)

Causes and solutions:

• 📶 VoWiFi requires activated VoLTE. Check in Settings → SIM cards. → VoLTE Challenges.
• 🔄 Outdated firmware. MIUI last-minute.
• 📱 Operator lock, call support and see if your rate supports IMS.

🟡 VoWiFi is turned on, but calls are not coming

What to do:

1. Reboot the phone.
2. Turn off and turn on Wi-Fi again.
3. Check if the router firewall blocks ports 500 and 4500 (required for the router) IMS).
4. Reset network settings: Settings → System → Reset settings → Reset mobile network settings.

🟢 VoWiFi works, but the battery goes down quickly

Decisions:

• 🔋 Turn off VoWiFi when it is not needed (for example, on the street).
• 📴 Enable Power Saving Mode for Wi-Fi: Settings → Battery → Energy saving regime → Limit background Wi-Fi activity.
• 🔄 Update the firmware - in new versions MIUI Optimized energy consumption IMS.

⚠️ Warning: If you lose your mobile internet after you turn on VoWiFi, it's a firmware bug. Try turning off VoLTE or reset your settings. APN (In the extreme case, roll back to the older version. MIUI.

FAQ: Frequent questions about VoWiFi in Xiaomi Redmi