Efficient spectrum utilization is crucial in mobile communications. As operators strive to provide faster data rates and better connectivity, carrier aggregation (CA) has become one of the most important features introduced in 3GPP R10 (LTE-Advanced) and further developed in 5G (NR).
1. Carrier Aggregation (CA) increases bandwidth and throughput by combining multiple component carriers (CCs). The bandwidth of each component carrier ranges from 20 MHz in LTE to 100 MHz in 5G (NR). Therefore, the total bandwidth of LTE-Advanced (5CCs) can reach 100 MHz, while the total bandwidth of 5G (NR) (16CCs) can reach 640 MHz. The principle is that by combining carriers, the network can send and receive more data simultaneously, thereby improving efficiency and user experience.
2. Aggregation Types: In 4G and 5G, carrier aggregation can be categorized based on how carriers are organized across or within different frequency bands:
Intra-band contiguous | Adjacent carriers within the same band | Band 3: 1800 MHz (10+10 MHz contiguous)
Intra-band non-contiguous | Carriers within the same band but with frequency separation | Band 40: 2300 MHz (20+20 MHz with a gap)
Inter-band aggregation | Carriers from different bands | Band 3 (1800 MHz) + Band 7 (2600 MHz)
The figure above visually illustrates the intra-band non-contiguous type, where both carriers belong to Band A but there is a gap in the spectrum between them.
3. Intra-band contiguous carrier aggregation (ICCA) works by combining adjacent carriers within the same band. Non-contiguous intra-band carrier aggregation (NCCA) goes a step further and allows aggregation of non-adjacent carriers within the same band. This is particularly important for operators dealing with fragmented spectrum allocations.
4. Intra-Band Non-Contiguous Carrier Aggregation (ICA) is a feature enabled in 4G and 5G to fully utilize fragmented spectrum. Carrier aggregation (CA) allows operators to combine multiple carriers (called component carriers (CCs)) to create wider bandwidth channels, thereby improving throughput and enhancing the user experience.
