Cellular Standards

Band Combination

Q: How is band combination notation interpreted?

Band combination notation uses a structured format: CA_BxY-BzW for LTE carrier aggregation, where Bx is the band number, Y is the bandwidth class (A=5-25 MHz, B=25-50 MHz, C=50-100 MHz), and the hyphen separates aggregated bands. Examples: CA_B3A-B7A = Band 3 (20 MHz) + Band 7 (20 MHz), CA_B3A-B3A = two carriers on Band 3 (intra-band contiguous CA). For 5G NR EN-DC (LTE anchor + NR): DC_B3A-n78A = LTE Band 3 (20 MHz) + NR n78 (100 MHz). For NR-CA: CA_n78A-n79A = NR n78 + NR n79. The number of supported combinations directly determines the device's RF front-end complexity and cost.

Q: Why do band combinations matter for device design?

Each band combination requires specific RF front-end hardware: filters, duplexers, switches, and power amplifiers that can simultaneously receive and/or transmit on the specified bands. A device supporting 100 band combinations may need 10+ RF filter paths with complex switching networks. Harmonic and intermodulation interference between bands must be characterized and mitigated for each combination. Adding a new band combination to a device may require new filter designs, additional switch paths, and extensive coexistence testing. This is why flagship smartphones support hundreds of combinations while budget devices support only a few dozen.

Q: How many band combinations exist in 3GPP specifications?

As of 3GPP Release 17, there are over 1,500 defined LTE CA combinations and thousands of NR and EN-DC combinations. No single device supports all of them; manufacturers select combinations relevant to their target markets. A flagship smartphone for the US market might support 200+ LTE CA combinations, 50+ EN-DC combinations, and 30+ NR-CA combinations. The 3GPP specification (TS 36.101 Annex A for LTE, TS 38.101-1 Annex A for NR FR1) lists all standardized combinations with their bandwidth classes and fallback configurations.

/band KOM-bih-NAY-shun/

A specification defining the set of frequency bands, channel bandwidths, and MIMO configurations a device supports for carrier aggregation (CA) in LTE or dual connectivity (DC) in 5G NR. Standardized in 3GPP TS 36.101 (LTE) and TS 38.101 (NR), band combinations are signaled during capability exchange. The notation CA_B3A-B7A means two carriers aggregated on Band 3 and Band 7 with class A bandwidth. The number of supported combinations drives RF front-end complexity and device cost.

Standard: 3GPP TS 36/38.101

LTE CA Combos: 1,500+

NR/EN-DC: Thousands

Understanding Band Combinations

Carrier aggregation allows a device to simultaneously receive (and sometimes transmit) on multiple frequency bands, dramatically increasing throughput. But supporting CA requires the device's RF front-end to handle multiple simultaneous signals with strict isolation requirements. Each band combination represents a specific hardware configuration that has been designed, tested, and standardized.

The explosive growth of band combinations reflects the complexity of modern cellular networks. A typical US market requires supporting LTE on Bands 2, 4, 5, 7, 12, 13, 14, 25, 26, 30, 41, 48, 66, 71 (14 bands), plus NR on n2, n5, n7, n12, n25, n41, n48, n66, n71, n77, n78 (11 bands), with dozens of CA/EN-DC combinations between them. Each requires validated RF filter designs and coexistence testing.

Band Combination Notation

LTE Carrier Aggregation:
CA_BxY-BzW (inter-band CA)
CA_BxY-BxY (intra-band contiguous CA)
Example: CA_B3A-B7A = B3(20 MHz) + B7(20 MHz)

EN-DC (LTE + NR):
DC_BxY-nZW
Example: DC_B3A-n78A = LTE B3 + NR n78

Bandwidth Classes:
A: ≤ 25 MHz (single carrier)
B: 25–50 MHz (two carriers)
C: 50–100 MHz (three carriers or wider)
D: 100–200 MHz

Common Band Combinations by Market

Market	Example Combo	Bands	Peak DL
US (T-Mobile)	DC_B66A-n41C	LTE B66 + NR n41 (100 MHz)	~2.5 Gbps
US (Verizon)	DC_B13A-n77C	LTE B13 + NR n77 (100 MHz)	~2.5 Gbps
Europe	DC_B3A-n78A	LTE B3 + NR n78 (100 MHz)	~2.0 Gbps
Japan	CA_n78A-n79A	NR n78 + NR n79	~3.5 Gbps
LTE 3CC	CA_B3A-B7A-B20A	B3 + B7 + B20	~300 Mbps

Common Questions

Frequently Asked Questions

How is band combination notation interpreted?

CA_BxY-BzW: Bx is band number, Y is bandwidth class (A = ≤25 MHz, B = 25 to 50 MHz, C = 50 to 100 MHz). EN-DC: DC_BxY-nZW (LTE anchor + NR). CA_B3A-B7A = Band 3 + Band 7 at 20 MHz each. DC_B3A-n78A = LTE Band 3 + NR n78. The number of supported combinations determines RF front-end complexity.

Why do band combinations matter for device design?

Each combination requires specific RF hardware: filters, duplexers, switches, PAs for simultaneous multi-band operation. A device with 100 combinations may need 10+ RF filter paths. Harmonics and intermodulation must be characterized per combination. Flagships support hundreds; budget devices support a few dozen.

How many band combinations exist in 3GPP specifications?

Over 1,500 LTE CA combinations and thousands of NR/EN-DC combinations as of Release 17. No device supports all. A US flagship supports ~200+ LTE CA, ~50+ EN-DC, and ~30+ NR-CA combinations. Standardized in TS 36.101 Annex A (LTE) and TS 38.101-1 Annex A (NR FR1).

Related Terms

← Band n79 (4.7 GHz) Band n1 →

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