5G NR Carrier Aggregation (CA) basics | Carrier Aggregation frequency bands

This page describes 5G NR Carrier Aggregation (CA) basics. It mentions Carrier Aggregation/Dual Connectivity LTE 5G NR frequency bands and benefits or advantages of carrier aggregation in wireless systems such as 5G NR. It mentions minimum requirements of carrier aggregation in 5G NR.

Introduction:
• The concept of CA is introduced in LTE Release-10.
• Carrier aggregation refers to concatenation of multiple carriers. This increases bandwidth and consecutively data rate of the system. LTE R-10 provides support for 5 CCs (Component Carriers).
• LTE supports five bandwidth options 1.4, 3, 5, 10 and 20 MHz. With maximum bandwidth and 5 CCs, LTE gives maximum bandwidth of 100 MHz. LTE R-13 (i.e. LTE Advanced-PRO), supports 32 CCs, hence 640 MHz can be achieved.
• 5G NR supports carrier aggregation with 16 CCs.
• Carrier aggregation of LTE and 5G NR carriers is also possible which is known as Dual Connectivity (DC).

• As mentioned in Carrier Aggregation (CA) two or more Component Carriers (CCs) are aggregated.
• A UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities.
• CA is supported for both contiguous and non-contiguous CCs.
• When CA is deployed frame timing and SFN are aligned across cells which can be aggregated.

As shown in the figure-1 there are three types of carrier aggregation in general.
• Intra-band contiguous
• Intra-band non-contiguous
• Inter-band non-contiguous
Refer carrier aggregation in LTE >>

5G NR Carrier Aggregation

• In 5G NR Phase-1, upto 16 CCs (both contiguous and non-contiguous) can be aggregated.
• Upto 1 GHz of spectrum can be aggregated.
• Carriers can use different numerologies (i.e. SCS, slots etc.)
• Transport block mapping is per carrier basis.
• Cross-carrier scheduling and joint feedback are supported.
• Carrier aggregation in 5G NR is used for both FR1 (below 6 GHz) and FR2 (above 6 GHz in mmwave range) frequency bands.

Minimum requirements of carrier aggregation in 5G NR

Following tables mentions minimum requirements of carrier aggregation in intra-band and inter-band modes. These tables are derived from 3GPP TS 38.133 document.

Dual Connectivity | LTE and 5G NR Carrier Aggregation Frequency Bands

In Dual connectivity carrier aggregation mode both LTE carriers and 5G NR carriers are combined. The frequency bands for this are mentioned in the table below.

Advantages of Carrier Aggregation

➤Bandwidth increases and hence data rates or throughputs increase for both uplink and downlink.
➤Network operators have choice to deploy in any of the three CA types.
➤It helps in aggregation of licensed and un-licensed spectrums.
➤The concept can be used for both TDD and FDD topologies.
➤It helps in improvement of network efficiency.
➤Refer advantages and disadvantages of carrier aggregation >>.

5G NR Numerology | 5G NR Terminology

5G NR Control channels | 5G NR Traffic Channels | 5G NR Reference Signals and sequences

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RF and Wireless Terminologies