Users of budget and mid-budget smartphones, including popular models Redmi i Poco, are often faced with a situation where the network indicator shows full signal strength, but calls are dropped, and the Internet is unstable. This problem can be caused by both external factors, such as distance from the operator's tower, and internal software settings MIUI or HyperOS. Often the reason lies in incorrect access points or a conflict in frequency bands that the phone tries to use by default.
Before taking the device to a service center, it is worth trying a number of independent steps to optimize the radio module. In this article, we will look at proven methods that allow you to stabilize your connection without losing data. You will learn how to correctly set the priority of networks, clear the cache of system communication applications and select the optimal SIM card slot so that the quality of communication on your Xiaomi becomes stable.
Diagnostics of the current communication problem
The first step in solving any technical problem is to accurately determine its source. The problem may not be with the smartphone itself, but with the tariff plan, the physical integrity of the SIM card, or the coverage of the operator in your region. If the phone shows the icon 4G or 5G, but the pages do not load, most likely the problem is in the APN access point settings, and not in the device antenna.
Try installing your SIM card in another phone of the same model or any other device. If the problem persists on another device, then the problem is with the operator or the plastic card itself. In the case when the connection works perfectly on another phone, but not on Redmi the reason lies in the software or hardware of a particular gadget.
⚠️ Attention: If you are using an old SIM card cut from Mini or Micro format using Nano-SIM scissors, this may be the cause of poor contact. The edges of such a card are often uneven and can scratch the contacts in the tray. It’s better to replace it in the operator’s cabin with a new Nano format.
It’s also worth checking whether the airplane mode or limited network mode is accidentally activated. Sometimes, after a firmware update, the settings are reset and the phone stops seeing certain frequencies used by your operator. To quickly check, enter the code in the dialer menu ##4636##to get to the testing menu.
Changing the network type and frequency priority
Modern smartphones are by default configured to automatically select the network type, often giving priority to the fastest standard, for example, 5G or 4G+. However, in areas of poor reception, the phone begins to constantly switch between standards, trying to “catch” the best signal, which leads to disconnections and rapid battery drain.
To fix this, you need to force the phone to switch to a more stable standard. Go to menu Settings → SIM cards and mobile networks → Network selection. Here you can disable 5G if your operator has not yet provided stable 5G coverage in your area. Often fixation on LTE (4G) gives a much more stable ping and voice quality than constant jumps between 3G and 5G.
For more advanced users, a hidden engineering mode is available that allows you to select specific frequency ranges (Bands). This is especially true if you are on the border of coverage of different towers. In the testing menu (called by the code ##4636##), select Phone information and find the drop-down list “Set up preferred network type.”
- 📡 NR/LTE/GSM/WCDMA —maximum search mode for all available networks, including 5G. Suitable for cities with dense coverage.
- 📶 LTE Only — forced operation only in 4G networks. Voice calls will work via VoLTE if the operator supports this technology.
- 📻 LTE/WCDMA/GSM — disables 5G search, saving battery power and stabilizing communication in the suburbs.
⚠️ Attention: When selecting the mode LTE Only on some firmware without the VoLTE function enabled, incoming calls may not go through, since the network 2G/3G will be completely disabled. Make sure that the VoLTE service is activated with your operator before applying this setting.
If the Internet disappears after changing the network type, simply restart the device. The radio module needs time to re-register in the network with new parameters.
Configuring and resetting APN access points
A frequent reason for slow Internet at full signal strength is incorrect access point (APN) settings. Carriers periodically update their gateway settings, and old settings stored in the phone's memory may conflict with current network requirements. This is especially true when changing the region or after flashing the device.
To correct the situation, you need to reset the APN settings to the operator’s factory values. Go to section Settings → SIM cards and mobile networks → Select your SIM card → Access points (APN). In the lower corner of the screen or in the menu (three dots), find the button Reset or Reset to default. After this, the phone will automatically download the latest settings from the operator.
If automatic reset does not help, you can create a new access point manually. The data to be filled in (point name, APN, proxy) can be found on the official website of your mobile operator. When entering manually, it is important to avoid typos, since even one extra space in the field APN can lead to complete inoperability of the mobile data.
| Parameter | Value (example for MTS) | Value (example for Beeline) | Value (example for Megafon) |
|---|---|---|---|
| Name | MTS Internet | Beeline Internet | Megafon Internet |
| APN | internet.mts.ru | internet.beeline.ru | internet |
| Authentication type | PAP or CHAP | PAP or CHAP | No or PAP |
| APN type | default,supl | default,supl | default,supl |
After making changes, be sure to restart your smartphone. The system will apply the new settings only after a complete power-on cycle. If the Internet appears, but is working slowly, check the “Proxy” field - it should be empty unless the operator has indicated otherwise.
Resetting the network and radio module settings
Sometimes errors accumulate in Android system files that prevent the correct operation of wireless interfaces. Resetting network settings is a secure procedure that removes all saved Wi-Fi passwords, paired Bluetooth devices and mobile network settings, returning them to their original state. This often solves problems when the phone gets stuck searching for a network.
To perform a reset, go to menu Settings → Connection and sharing → Reset Wi-Fi, mobile networks and Bluetooth. On some versions of MIUI, this item may be located in the Advanced settingssection. Press the button Reset settings and confirm the action with the screen unlock password.
☑️ Checklist before resetting the network
This procedure does not affect your personal files, photos or installed applications. It only affects communication modules. After the reboot, the phone will begin to re-register with the network, requesting fresh configuration data from the tower. In most cases, this eliminates communication protocol errors.
If the problem persists even after a reset, it is worth checking to see if you have any optimization applications or antiviruses installed that can aggressively monitor the network. Try uninstalling recently installed apps related to traffic management or changing IMEI (which is illegal and dangerous).
Physical factors and SIM card location
Do not underestimate the impact of the physical location of the SIM card and tray condition on call quality. In dual-SIM smartphones Redmi slots may have different antenna connection architectures. Often the first slot (SIM 1) is connected directly to the main module, while the second may work through an adapter or have a less stable contact.
Try moving the SIM card to another slot. If you use two cards, try leaving only one, the one used for the Internet and calls, and test the connection. Also carefully inspect the contacts on the SIM card itself. If they become dull or oxidized, gently wipe them with a regular school eraser or alcohol wipe.
Another important physical factor is the smartphone case. Metal inserts, magnetic fasteners or too thick protective glass can shield the signal from the antennas, which in modern models are often built into the frame of the case. Remove the case and check if the signal level has improved. If yes, then the reason is in the accessory.
⚠️ Attention: Never use metal antenna stickers that are sold in cheap accessory stores. Not only do they not amplify the signal, but they can also disrupt the operation of the standard antenna system of the smartphone, creating spurious interference.
Why does the second slot work worse?
In many budget models, the second slot is hybrid or has a simplified radio module connection scheme. This was done to reduce the cost of the design. If communication stability is critical to you, use the main SIM in the first slot.
The impact of system and firmware updates
Software plays a key role in controlling the radio module. Developers Xiaomi regularly release updates that contain fixes for communication errors and optimization of work with networks of different operators. However, sometimes new firmware versions, especially beta versions, can, on the contrary, introduce new bugs.
Check for updates in the section Settings → About phone → MIUI version. If you have an older version installed, the update may bring new modem drivers. If the problem appeared immediately after updating to a new version, it may be worth waiting for the next patch or rolling back to the previous stable build.
It is important to distinguish between global firmware versions and versions for China (CN). Chinese versions may not support some frequencies (Bands) used by Russian or European operators, or may have incorrectly configured default APN profiles. Using Global ROM usually guarantees better compatibility with local networks.
It is also worth paying attention to the Network Assistant feature or similar system utilities that may be enabled by default. They try to switch you between Wi-Fi and mobile data to speed things up, but they often do it incorrectly, causing session breaks. Disable the function Wi-Fi Assistant in the Wi-Fi settings.
The stability of the connection depends 50% on the relevance of the modem’s basic firmware. Regular system updates are the easiest way to get fixes from the manufacturer.
Frequently asked questions (FAQ)
Why does Redmi lose connection only indoors?
This may be due to the use of high-band frequencies (for example, 2600 MHz), which provide high speeds but do not penetrate walls well. Try to select preferably 3G or 900 MHz in the network settings (if available through the engineering menu), since low frequencies pass through obstacles better.
Is it possible to amplify the signal programmatically without root access?
It is impossible to radically amplify a physical signal programmatically, since the transmitter power is limited by hardware and by law. However, you can stabilize the connection by fixing the network type (for example, only 4G) and resetting the APN settings, which will prevent the phone from constantly switching between towers.
Does the phone's memory being full affect the quality of the connection?
Indirectly - yes. If the system partition is full, the operating system may not work correctly with background services, including radio module services. Free up at least 1-2 GB of free memory for stable operation of the system.
What to do if the phone says “No network” after a reset?
Make sure that the SIM card is not blocked by a PIN code or operator due to debt. Try inserting the card into another phone. If it works there, your Redmi may have an IMEI failure (rarely, but it happens after unsuccessful firmware), and you will need to reflash it via a computer.