Carrier aggregation in LTE or what to look for when buying the next smartphone
The speed of the mobile Internet depends on both the carrier and your device. When the description of the operator’s network uses the terms 4G + or LTE-Advance, it means that carrier aggregation technology is supported on the network, which provides higher mobile Internet speeds. What is it, how it has already been implemented on the networks of Russian mobile operators, what smartphones support it - this article is about it.
To understand the principle of this technology, let's imagine the road. It is obvious that the capacity of a road with two lanes is higher than that of a road with one lane. A track with three or even four lanes allows you to skip an even greater number of different cars moving at different speeds.
Similarly to roads, there are carriers in cellular communication - radio frequencies on which useful information is transmitted. If you aggregate (combine) carriers for data transmission, you can get more network bandwidth, and hence the speed of the mobile Internet of a particular subscriber.
In Russia, for the networks of the 4th generation, four frequency bands are used today:
The width of the band and the coverage area of ​​each range are different for operators. For example, the international version of the generally good Xiaomi mi5 smartphone does not support the 20th range. For Russian subscribers, this may be critical, since Despite the small band at 5 MHz in this range, power limitations and different coverage for different operators, the band itself has high indoor penetration, i.e. The smartphone is more likely to transfer data indoors.
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Another example, MegaFon has 40 MHz of continuous spectrum of the 7th band, while other operators have only 20 MHz. This gives a significant advantage to the operator (for high speeds and capacity), although not fully implemented.
For MTS subscribers it is certainly important to check whether the smartphone supports the 38th range - MTS has high coverage of this range in Moscow. In an advantageous position, for example, were users of iPhone 6S, 7, their smart phones work with the 38th range.
Making further the analogy with the roads, we can say that the new smartphone should be able to drive along all four roads (lanes).
Thus, when choosing a new smartphone, if you care about the speed of the mobile Internet, you should pay attention when reading the specification whether the device ideally supports all four ranges - 3, 7, 20, 38. Today there are few such smartphones, the required minimum is availability ranges 3 and 7, the average option - the presence of 3, 7 and 20 ranges.
Now let's talk about carrier aggregation itself.
At present, Russian operators support the following carrier aggregation combinations:
Thus, the maximum configuration is available for MegaFon in Moscow and St. Petersburg - this is the aggregation of three components - 20 MHz from the 3rd band and 20 + 20 MHz from the 7th band.
Subscriber devices are classified by category. The most common today are the devices of the 4th category CAT4. This means that the maximum achievable speed of the mobile Internet at the reception (downlink or DL) can be 150 Mbps, per transmission (uplink or UL) - 50 Mbps. It is important to note that this is the maximum attainable speed in ideal conditions - the main ones are that you are not far from the tower, besides you there are no more subscribers in the cell, optical transport is connected to the base station, etc.
4th category smartphones work for all 4 Russian operators, 6th category devices can show maximum results in MegaFon, MTS and Beeline networks, but devices of the 9th category can show up to the maximum only in MegaFon network.
Carrier aggregation appears in devices starting from the 6th category. Devices with CAT6 support the aggregation of two carriers, and is already in our market. This, for example, Lenovo Moto P2, Lenovo Moto Z Play, Lenovo Moto Z, Sony Xperia X, Xiaomi Mi Note 2, Apple 6S.
Devices of the 9th category just started to appear. These are HTC M10, Apple iPhone 7, Sony Xperia XZ. The appearance of smartphones of the 12th and 16th categories is expected in 2017, first of all pay attention to the flagship models of ASUS and Sony. Peak speeds will be possible if operators implement additional 4x4 MIMO technologies and 256 QAM. If the 256 QAM modulation is enabled as a result of updating the operator’s infrastructure software, 4x4 MIMO technology (4 antennas for reception, 4 antennas for transmission) will require an investment in antenna management. In this regard, the maximum peak speeds will be possible at the beginning only in hot spots such as business / shopping centers, train stations, etc.
How to find out the category of the smartphone? This is not a trivial task. A good sign is the used chipset (processor / modem). You can learn it, for example, here . For devices of the 6th category, be guided by Qualcomm Snapdragon 625, 626, 653, 435, and for devices of the 9th category - Qualcomm Snapdragon 820 and 821. This unfortunately cannot guarantee the maximum result, for example, the ZTE Z11 smartphone is built on the flagship Snapdragon 820 chipset, but the global version will only work as a 4th category device.
Today, from the 6th category of smartphones can be recommended - Moto Z and Xiaomi Mi Note 2, 9th category - Sony Xperia XZ and, if you are ready to overpay for the brand - iPhone 7. The author did not have the opportunity to test the Samsung Galaxy S7, and In particular, which combinations of aggregation of Russian operators are supported, therefore, colleagues, who knows, please write in the comments.
Happy New Year!
To understand the principle of this technology, let's imagine the road. It is obvious that the capacity of a road with two lanes is higher than that of a road with one lane. A track with three or even four lanes allows you to skip an even greater number of different cars moving at different speeds.
Similarly to roads, there are carriers in cellular communication - radio frequencies on which useful information is transmitted. If you aggregate (combine) carriers for data transmission, you can get more network bandwidth, and hence the speed of the mobile Internet of a particular subscriber.
In Russia, for the networks of the 4th generation, four frequency bands are used today:
| Frequency range | 1800 MHz | 2600 MHz | 800 MHz | 2600 MHz |
|---|---|---|---|---|
| 3GPP Grade Number | 3 | 7 | 20 | 38 |
| Channel separation | Fdd | Fdd | Fdd | Tdd |
| Signal propagation (coverage area, room penetration) | the average | low | high | low |
| Prevalence on smartphones | high | high | Average growing | Low growing |
The width of the band and the coverage area of ​​each range are different for operators. For example, the international version of the generally good Xiaomi mi5 smartphone does not support the 20th range. For Russian subscribers, this may be critical, since Despite the small band at 5 MHz in this range, power limitations and different coverage for different operators, the band itself has high indoor penetration, i.e. The smartphone is more likely to transfer data indoors.
')
Another example, MegaFon has 40 MHz of continuous spectrum of the 7th band, while other operators have only 20 MHz. This gives a significant advantage to the operator (for high speeds and capacity), although not fully implemented.
For MTS subscribers it is certainly important to check whether the smartphone supports the 38th range - MTS has high coverage of this range in Moscow. In an advantageous position, for example, were users of iPhone 6S, 7, their smart phones work with the 38th range.
Making further the analogy with the roads, we can say that the new smartphone should be able to drive along all four roads (lanes).
Thus, when choosing a new smartphone, if you care about the speed of the mobile Internet, you should pay attention when reading the specification whether the device ideally supports all four ranges - 3, 7, 20, 38. Today there are few such smartphones, the required minimum is availability ranges 3 and 7, the average option - the presence of 3, 7 and 20 ranges.
Now let's talk about carrier aggregation itself.
At present, Russian operators support the following carrier aggregation combinations:
| Operator | Megaphone | Mts | Beeline | Tele 2 |
|---|---|---|---|---|
| Combinations | 7 + 7, 3 + 7, 3 + 7 + 7 | 3 + 38, 3 + 7 | 3 + 7 | - |
Thus, the maximum configuration is available for MegaFon in Moscow and St. Petersburg - this is the aggregation of three components - 20 MHz from the 3rd band and 20 + 20 MHz from the 7th band.
Subscriber devices are classified by category. The most common today are the devices of the 4th category CAT4. This means that the maximum achievable speed of the mobile Internet at the reception (downlink or DL) can be 150 Mbps, per transmission (uplink or UL) - 50 Mbps. It is important to note that this is the maximum attainable speed in ideal conditions - the main ones are that you are not far from the tower, besides you there are no more subscribers in the cell, optical transport is connected to the base station, etc.
| Subscriber category | Max. DL speed, Mbps | Carrier aggregation | Additional technologies |
|---|---|---|---|
| CAT4 | 150 | - | - |
| CAT6 | 300 | 2x20 MHz | - |
| CAT9 | 450 | 3X20 MHz | - |
| CAT12 | 600 | 3X20 MHz | 4x4 MIMO, 256 QAM |
| CAT16 | 980 | 4X20 MHz | 4x4 MIMO, 256 QAM |
4th category smartphones work for all 4 Russian operators, 6th category devices can show maximum results in MegaFon, MTS and Beeline networks, but devices of the 9th category can show up to the maximum only in MegaFon network.
Carrier aggregation appears in devices starting from the 6th category. Devices with CAT6 support the aggregation of two carriers, and is already in our market. This, for example, Lenovo Moto P2, Lenovo Moto Z Play, Lenovo Moto Z, Sony Xperia X, Xiaomi Mi Note 2, Apple 6S.
Devices of the 9th category just started to appear. These are HTC M10, Apple iPhone 7, Sony Xperia XZ. The appearance of smartphones of the 12th and 16th categories is expected in 2017, first of all pay attention to the flagship models of ASUS and Sony. Peak speeds will be possible if operators implement additional 4x4 MIMO technologies and 256 QAM. If the 256 QAM modulation is enabled as a result of updating the operator’s infrastructure software, 4x4 MIMO technology (4 antennas for reception, 4 antennas for transmission) will require an investment in antenna management. In this regard, the maximum peak speeds will be possible at the beginning only in hot spots such as business / shopping centers, train stations, etc.
How to find out the category of the smartphone? This is not a trivial task. A good sign is the used chipset (processor / modem). You can learn it, for example, here . For devices of the 6th category, be guided by Qualcomm Snapdragon 625, 626, 653, 435, and for devices of the 9th category - Qualcomm Snapdragon 820 and 821. This unfortunately cannot guarantee the maximum result, for example, the ZTE Z11 smartphone is built on the flagship Snapdragon 820 chipset, but the global version will only work as a 4th category device.
Today, from the 6th category of smartphones can be recommended - Moto Z and Xiaomi Mi Note 2, 9th category - Sony Xperia XZ and, if you are ready to overpay for the brand - iPhone 7. The author did not have the opportunity to test the Samsung Galaxy S7, and In particular, which combinations of aggregation of Russian operators are supported, therefore, colleagues, who knows, please write in the comments.
Happy New Year!
Source: https://habr.com/ru/post/318588/
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