Band 41 (2500 MHz)
Understanding Band 41
Band 41 has had a turbulent history. Clearwire used it for WiMAX starting in 2008, then Sprint acquired Clearwire and converted the network to LTE-TDD. Sprint's limited subscriber base meant the 194 MHz of spectrum was largely underutilized for years. When T-Mobile acquired Sprint in 2020, it inherited this massive spectrum asset and immediately began deploying 5G NR with massive MIMO, transforming Band 41 from a liability into the backbone of the largest US 5G mid-band network.
The TDD nature of Band 41 is critical for massive MIMO. Channel reciprocity (same frequency for UL and DL) allows the base station to estimate the downlink channel from uplink measurements, enabling beamforming with 64 antenna elements without requiring explicit CSI feedback from the device. This multiplies spectral efficiency by 4 to 8× compared to conventional MIMO, allowing a single 100 MHz n41 carrier to deliver aggregate throughput exceeding 1 Gbps per sector.
Band 41 Technical Parameters
2496 – 2690 MHz (194 MHz total TDD)
BRS: 2496–2572 MHz | EBS: 2572–2690 MHz
NR Configuration (n41):
SCS: 30 kHz | Max channel BW: 100 MHz
Peak DL (100 MHz, 256-QAM, 4-layer): ~2.3 Gbps
Path Loss vs. C-Band:
ΔPL = 20 log(2600/3600) = −2.8 dB advantage
~30% more coverage area per cell
Massive MIMO Gain:
64T64R array gain: ~18 dBi per beam
MU-MIMO layers: up to 16 simultaneous users
US Mid-Band 5G Comparison
| Band | Frequency | BW (typical) | Operator | Capacity |
|---|---|---|---|---|
| n41 (2.5 GHz) | 2496-2690 MHz | 60-100 MHz | T-Mobile | Highest (wide BW + MIMO) |
| n77 (C-Band) | 3700-3980 MHz | 40-100 MHz | Verizon, AT&T | High (shorter range) |
| n78 (3.5 GHz) | 3300-3800 MHz | 40-100 MHz | Global | High (most deployed 5G) |
| n66 (AWS) | 1710-2200 MHz | 10-20 MHz | T-Mobile, AT&T | Moderate (DSS limited) |
Frequently Asked Questions
Why is Band 41 important for 5G NR?
194 MHz of contiguous TDD spectrum enables 100 MHz NR carriers with 64T64R massive MIMO. T-Mobile holds up to 160 MHz in most US markets. A single 100 MHz n41 carrier delivers 1 to 2 Gbps peak. At 2.5 GHz, coverage is 2.9 dB better than C-band (3.5 GHz), making n41 T-Mobile's primary 5G differentiator in the US market.
What is the BRS/EBS spectrum?
Band 41 in the US is allocated as BRS (2496 to 2572 MHz, commercially licensed) and EBS (2572 to 2690 MHz, educational institutions). Sprint acquired BRS and secured long-term EBS leases, giving T-Mobile 150 to 194 MHz in most markets. The FCC's 2020 EBS auction for unlicensed rural areas raised $7.3 billion.
How does TDD benefit massive MIMO at 2.5 GHz?
TDD uses the same frequency for UL and DL, enabling channel reciprocity. The base station measures the downlink channel from uplink transmissions without requiring CSI feedback. A 64T64R array forms narrow beams serving 4 to 16 users simultaneously (MU-MIMO), multiplying spectral efficiency 4 to 8×. FDD bands cannot exploit this because UL and DL frequencies differ.