FR1 vs FR2 vs FR3: Why FR3 Powers 6G

As wireless networks are evolving from 5G to 6G, the management and utilization of radio frequency spectrum are undergoing changes. While 5G introduced dual frequency bands viz. FR1 and FR2, the new spectrum band FR3 has been introduced in 6G wireless technology. Understanding differences between FR1, FR2 and FR3 is based on how they balance demands of vast coverage, extreme capacity and energy efficiency.

FR1 (Sub-6GHz)

• It spans from ~ 410 MHz to 7.125 GHz.

• It has been used as legacy 3g/4g bands as well as 5G mid bands (i.e. c-band).

• It is known for its excellent propagation characteristics.

• It provides fundamental coverage blanket for rural, suburban and widespread urban mobile users.

• FR1 Advantages :

  • Signals in the FR1 range can travel distances of several kilometers from a single macro tower.
  • This makes it highly cost effective for providing wide area and ubiquitous coverage.
  • Easily penetrate buildings, foliage and vehicles.

• FR1 Disadvantages :

  • Primary drawback is spectrum scarcity.
  • As this band of frequencies have been used widely by legacy technologies, it is difficult to get contiguous wide band of frequency spectrum.
  • FR1 offers lower overall data rates and capacity compared to higher bands.

FR2 (Millimeter-Wave)

• It spans from ~ 24.25 GHz to 71 GHz.

• It represents extreme high end of active commercial cellular frequency spectrum.

• It is used as ultra high capacity hotspots.

• FR2 is ideal for stadiums, dense urban street canyons, convention centers and specialized enterprise deployments where thousands of users demand massive bandwidth simultaneously.

• FR2 Advantages :

  • It offers massive strip of untapped, continuous spectrum.
  • These ultra wide channels can offer multi-gigabit data speeds.
  • It offers virtually zero latency connections.
  • FR2 band is considered to be king of capacity.

• FR2 Disadvantages :

  • This band suffer from severe free space path loss.
  • FR2 frequencies will incur high atmospheric attenuation.
  • These frequencies are easily blocked by physical obstacles such as walls, trees, tinted glass and even human bodies.
  • Use of FR2 band requires dense network of small cells closer to user and typically they should be in line of sight (LOS).

FR3 (centimeter-wave)

• It spans from ~ 7.125 GHz to 24.25 GHz.

• As research in 6G technology progresses, use of sub-THz presents enormous hardware and physical challenges. Hence it has been decided to use FR3 band which sits perfectly between FR1 and FR2.

• It is considered as foundation for 6G technology.

• FR3 will provide the wideband capacity needed for next-generation applications (like XR and digital twins) while utilizing existing macro-tower infrastructure.

• FR3 Advantages :

  • Offers wider bandwidths than FR1, enables data rates that approach mmwave speeds.
  • FR3 can overcome its high path loss limitation by using ultra massive MIMO. This allows FR3 to achieve coverage parity with existing FR1 macro cell towers.
  • Hence operators can deploy high capacity 6G without needing to build a costly, dense grid of new small cells.

• FR3 Disadvantages :

  • As FR3 requires ultra massive MIMO antenna arrays to maintain coverage, its hardware complexity increases significantly.
  • Furthermore, this spectrum is currently crowded with incumbents, including satellite communications and military/defense radars. To overcome this challenge, it requires advanced dynamic spectrum sharing and coexistence strategies.

Key differences

Following table mentions difference between FR1, FR2 and FR3 bands.

Summary

FR3 is poised to become the pivotal bridge in the 6G era, unlocking the massive bandwidth required for next-generation technologies while leveraging the economical footprint of the macro towers we already have today.