[EXCLUSIVE] Xiaomi Redmi Note 7 (Pro) network issues/problems: Carrier aggregation likely incompatible with Indian networks

The Samsung Galaxy S10 5G is the first commercially available Android smartphone which is capable of harnessing the power of the next generation cellular connection technology. While 5G is still at its infancy, terms like ‘massive MIMO’, ‘carrier aggregation’, ‘QAM’ etc. are getting popular.

As a matter of fact, those technical jargons are not specifically related to 5G. In wireless telephony, these are commonly used methods to boost network performance. Of course you can create a ‘fake’ 5G connection on top of the extra juice, but that’s not directly related with this story.

The carrier aggregation part is rather interesting. Wireless providers use this simple but effective solution to combine two or more component carriers (frequency blocks) into one data channel to enhance the data capacity. It is possible to combine carriers in the same or different frequency bands.

As a final result, individual users can get much more better data rate in their phones.

To get the full benefit of carrier aggregation (CA), the phone (to be more precise, the cellular modem) should have seamless support of different possible aggregations scenarios, such as:

• intra-band contiguous
• intra-band, non-contiguous
• inter-band

Regular Android users may not prefer to dive into the technical details, but they can easily notice the little change in their status bar. When carrier aggregation is used (known as LTE Advanced), the phones should display ‘4G+’ instead of regular ‘4G’.

However, it is not a very reliable method as wireless providers and/or smartphone vendors can modify the icon. But manual speedtest or apps like Network Signal Guru can accurately display whether you’re benefitted using carrier aggregation or not.

Interestingly, Redmi Note 7 as well as Redmi Note 7 Pro users in India are facing low data rate/slow internet connection speed using mobile data since the release. Multiple reports suggest that the phones are unable to utilize the 4G+ (LTE-Advanced) connection, which results in poor performance.

Unable to latch on any 4g+ network.

Tried with airtel and jio both.

Device: Redmi Note 7 Pro (India)

(Source)

Band 40 20mhz +10mhz Carrier Aggregation (4G+) is neither working on Airtel nor on Jio.

Device: Redmi Note 7

(Source)

According to user reports, the issue is widespread and can be experienced on multiple networks such as Vodafone, Jio, Airtel etc. While there is no issue with signal strength, the LTE connection speed is drastically affected.

The internet works sometimes but when I swap internet between sim cards or keep my phone locked for some time then after unlock speed is restricted to 10 to 20 kbps then I have to restart, reset apn, change sim solt and by some luck it works again. Even is security app.. “The turn off data when screen is locked” is set to never

(Source)

same here too with my note 7..So i connect wifi through my other phone, then i get a better speed in my note7…if i use and on my internet in my note 7, speed is very slow….compare to my old cheap phone…

(Source)

We investigated a little and came to know that Xiaomi internally collected logs and bugreports from the affected users and conducted some tests. The company representative allegedly acknowledged that the carrier aggregation (CA) implementation on these phones may not be compatible in India!

Wait, there’s more! The current official specification for Redmi Note 7 Pro does not list ‘4G+’ anywhere – its says the following:

When using both SIM card slots, either card can be set as the primary card, which supports 4G/3G/2G calling and data

However, we are able to get our hands on the original spec list where they clearly mentioned 4G+ support in the same phone.

Carrier aggregation support is dependent on network operators as well. We have also spotted a truckload of user feedback regarding improper CA implementation in various Xiaomi, Redmi and Poco devices under different operators across the world.

Pocophone does not aggregate any of the given LTE frequencies. It connects to a single frequency only. There is no 2CA or 3CA.

My main phone (Galaxy S9+) aggregates up to 3 frequencies (3CA) when using the same SIM card and in the same location and it results in much higher DL/UL speeds.

(Source)

Redmi Note 7 Pro was exclusively launched in India back in February and is still selling like hotcakes. Nevertheless, selling a phone in a region without optimized network configuration is straightaway a bad practice.

Technically, it is possible to introduce new carrier aggregation methods with newer modem and baseband via OTA update. But looking at the current scenario, I really doubt Xiaomi is planning to do so in near future.

Are you facing slow internet speed on your Redmi Note 7 or Note 7 Pro? Let us know by commenting below.

Thanks Ravinder Singh for the assistance.

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