Introduction to the classification and development history of carrier aggregation

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Introduction to the classification and development history of carrier aggregation [Copy link]

Spectrum resources are scarce, and each frequency band is limited to a small section. Therefore, carrier aggregation needs to support multiple methods. Take two-carrier aggregation as an example:

If two carriers have the same frequency band and are adjacent to each other, with continuous spectrum, it is called intra-band continuous carrier aggregation.

If the frequency bands of two carriers are the same, but the spectrum is discontinuous and there is a gap in between, it is called discontinuous carrier aggregation within the frequency band.

If the frequency bands of the two carriers are different, it is called inter-band carrier aggregation.

These three methods cover all situations. No matter how many ways you come, they only go one way. No matter how many carriers there are, they can be tied into one.

Each carrier participating in carrier aggregation is called a component carrier (CC). Therefore, 3-carrier aggregation can also be called 3CC.

These carriers work together and need to coordinate with each other, so there must be a distinction between primary and secondary carriers.

The so-called primary carrier is the carrier that carries signaling and manages other carriers, also called Pcell (Primary cell).

Auxiliary carriers are also called Scells (Secondary cells). They are used to expand bandwidth and enhance rates. The primary carrier can decide when to add or delete them.

The primary and secondary carriers are relative to the terminal. For different terminals, the working primary and secondary carriers may be different. In addition, the multiple carriers participating in the aggregation are not limited to the same base station, but may also come from adjacent base stations.

After the introduction of carrier aggregation in 4G's LTE-Advanced protocol, the technology has been running wild like a wild horse, from the initial 5-carrier aggregation with a total bandwidth of 100MHz to the subsequent 32-carrier aggregation with a total bandwidth of up to 640MHz!

In the 5G era, although the number of carriers that can be aggregated is only 16, the carrier bandwidth of 5G is too large.

The maximum bandwidth of a single carrier in Sub6G is 100MHz, and 16 carriers are aggregated to a total of 1.6GHz bandwidth; the millimeter wave band is even more exaggerated, with a maximum bandwidth of 400MHz for a single carrier, and 16 carriers are aggregated to a total of 6.4GHz bandwidth!

The wheel of time rolls forward.

If you want to know more related knowledge, please read the popular science article: Let’s talk about carrier aggregation (Part 1) .