Carrier Aggregation (CA) is a technique in LTE-Advanced and 5G NR that combines multiple component carriers to increase the total bandwidth available to a single device. It allows simultaneous use of spectrum from different bands or within the same band, significantly boosting peak throughput.
What is Carrier Aggregation?
The bandwidth-boosting technique that combines multiple carriers for higher throughput in LTE and 5G.
Detailed explanation
Carrier Aggregation allows a device to simultaneously receive (and transmit on) multiple component carriers (CCs). In LTE-Advanced, up to 5 CCs can be aggregated for a maximum of 100 MHz total bandwidth. In 5G NR, up to 16 CCs can be combined, supporting bandwidths exceeding 1 GHz in millimeter-wave bands.
CA is classified into three types: intra-band contiguous (adjacent carriers in the same band), intra-band non-contiguous (separate carriers in the same band) and inter-band (carriers from different bands). Inter-band CA is the most common deployment, allowing operators to combine their spectrum holdings across different frequency layers.
The primary component carrier (PCell) handles RRC signalling and NAS procedures, while secondary carriers (SCells) provide additional bandwidth for user data. SCells are activated and deactivated dynamically based on traffic demand and radio conditions. The device reports separate measurement results for each component carrier.
The CA combination supported by a device is reported in its UE Capabilities message. Common European combinations include CA_3A-7A (Band 3 + Band 7), CA_1A-3A-7A (three carriers) and CA_3A-7A-20A. Verifying that the expected CA combination is activated in the field is essential for throughput optimization.
CA types
| Type | Description | Example |
|---|---|---|
| Intra-band contiguous | Adjacent carriers, same band | CA_7C (2x Band 7) |
| Intra-band non-contiguous | Separate carriers, same band | CA_3A-3A |
| Inter-band | Different frequency bands | CA_3A-7A-20A |
How HiCellTek monitors Carrier Aggregation
The RF Monitor module in HiCellTek displays all active component carriers with their individual EARFCN, PCI, bandwidth, RSRP and SINR. The UE Capabilities module decodes the supported CA combinations from the device. Together, they allow engineers to verify CA activation and diagnose configuration issues.
Frequently asked questions
What is Carrier Aggregation in LTE?
What is the difference between intra-band and inter-band CA?
How do I verify Carrier Aggregation is active?
HiCellTek shows all active carriers, CA combinations and per-carrier KPIs on Android smartphones.