Breakthrough in Ultra High-Speed Wireless Backhaul Paves the Way for 5G and 6G Connectivity
The wireless backhaul market has the potential to drive incremental growth due to rapid network expansion, dense network deployments, and a rise in global mobile data traffic.
Currently, many links between base stations rely on fiber-optic cables due to their ability to provide high bandwidth over long distances with minimal loss. However, wireless backhaul is becoming an increasingly important option, especially in dense urban cores and hard-to-reach rural sites where laying fiber optics is costly or impractical. To meet the exploding capacity demand of 5G and soon-to-be-6G, telecom operators are moving wireless backhaul links to higher carrier frequencies. These higher frequency bands offer a wider contiguous spectrum, and therefore much higher data rates.
A report from the global telecommunications company Ericsson showed that adoption of E-band is growing in telecom backhaul systems. Specifically, the 71–76 GHz and 81–86 GHz frequency ranges are already being used in telecom backhaul systems. Concurrently, research into new spectrum continues for future backhaul applications, with recent research reporting breakthroughs in WR6.5 band (110 – 170 GHz), and even higher frequency ranges.
In June 2025, Keysight, NTT, and NTT Innovative Devices announced a world record data rate achievement of 280 Gbps in J-band (220 - 325 GHz), also known as WR3.4 band (220 - 330 GHz). This breakthrough signal speed was generated using a wideband 300 GHz amplifier and high-precision distortion compensation technology.
Overcoming Power and Distortion Challenges
Key challenges in researching ultra high-speed wireless communication exceeding 100 Gbps include generating high-power and achieving high-speed modulated signals while mitigating path loss. Increasing signal power and speed cause more signal distortions, which must also be mitigated. Here is a look at notable efforts to solve ultra high-speed wireless communication challenges:
High-Power Signal Generation with NTT’s New IC: NTT and NTT Innovative Devices developed a wideband amplifier module using Indium Phosphide (InP) technology. This new integrated circuit achieved a saturated output power of +9.1 dBm, enabling high-power signal generation at 0 dBm — about 8× higher than previous systems.
Device Characterization Using Keysight’s Vector Component Analyzer: To generate and analyze signals, the team used Keysight’s Vector Component Analyzer which integrates:
- The M8199A arbitrary waveform generator (AWG)
- Virginia Diodes Inc. (VDI) frequency extenders
- The N524XB PNA-X microwave network analyzer
The intermediate frequency (IF) signals generated by the AWG were up-converted and down-converted in the WR3.4 frequency range with VDI’s frequency-extender modules, which maintain linearity across the band. This setup enabled precise signal synthesis and measurement at 35 GBaud 256-QAM, achieving the record-breaking 280 Gbps throughput.
Signal Integrity via Keysight’s Pre-Emptive Distortion Compensation: To counteract nonlinearities and maintain signal fidelity at high power levels, Keysight applied advanced digital predistortion (DPD) techniques. These pre-emptively corrected for amplifier distortion, ensuring high-quality, low-error signal transmission even at extreme frequencies.
Linda Clarkson
Dr. Tom Crowe, CEO and Founder of VDI, said: “Pushing coherent modulation into the sub-THz range demands ultra-low-noise frequency converters with minimal signal distortion and exceptional instantaneous bandwidth. Our frequency extenders, coupled with Keysight’s baseband fidelity, show that commercial test equipment is ready to push these technological boundaries.”
Joe Rickert, Vice President and Head of Keysight's High Frequency Center of Excellence, said: “As 5G networks mature and strain under surging data demands, next-gen base station backhaul solutions must evolve to keep pace. This breakthrough demonstrates how sub-THz innovation can complement and, in some scenarios, outpace fiber in agility and cost efficiency.”
As enterprises drive toward commercial 6G, mobile backhaul is paving the way for a new era — one defined not only by physical optic fiber cables, but also by over-the-air transmission with ultra-wideband sub-THz technology.
