Vendors lengthen the range of 5G millimeter-wave transmissions

Two wireless vendors say they have collaborated to significantly extend the useful range of millimeter-wave 5G transmissions beyond what had been widely considered its limits.

Qualcomm and Ericsson have worked together in separate trials with two other companies to boost that distance from less than a mile (1.6km) to 3.8km in one case and to 5km-plus in the other, the companies claim.

In order to do so, they had to work around the loss of power that the signals suffer over distance because rain disperses them and molecules of oxygen and water vapor in the air absorb them. They also can’t penetrate solid objects. As a result, millimeter waves have traditionally been thought to have the potential to carry a great deal of data but only over relatively short distances compared to longer wavelengths.

To overcome these issues, Ericsson says it has written a software upgrade called Extended Range for its existing carrier-grade 5G radio hardware that helps make the longer distance transmissions possible. It also used a customer-premises device equipped with a Qualcomm millimeter-wave antenna module.

“With the extended range software, the base station is able to detect millimeter wave signals arriving with long propagation delay from the device,” according to an Ericsson spokesperson. The upgrade “enables the communication between a base station and devices at long propagation delay, longer than what is typically the case in mobile broadband type of deployment.”

The 3.8km trial in conjunction with Casa Systems took place in Victoria, Australia, in June. The 5km trial was performed in Wisconsin in collaboration with U.S. Cellular, according to Ericsson.

The company says the Wisconsin trial achieved data speeds of more than 100Mbps. The potential speed of millimeter wave bandwidth is 1-3Gbps.

Millimeter waves occupy a band of electromagnetic spectrum in frequencies from 30GHz to 300GHz, and the Federal Communications Commission (FCC) has auctioned 5G licenses for specific millimeter-wave bands: the 28GHz band, the 24GHz band, and the upper 37GHz, 39GHz, and 47GHz bands.

Two other spectrum bands below the millimeter range are designated for 5G: low-band (600MHz, 800MHz and 900MHz bands) and mid-band (2.5GHz, 3.5GHz and 3.7-4.2GHz bands), according to the FCC.

Low-band and mid-band signals aren’t hampered by rain, humidity, and oxygen molecules, so they can travel much farther than millimeter waves and still effectively carry data. The downside is they deliver it at lower bandwidth—30-250Mbps for low-band and 100-900Mbps for mid-band.

The millimeter-wave frequency used in the Australia trial was 28GHz, and the methods used can work for higher frequencies, according to the Ericsson spokesperson. “However the higher the frequency the larger the propagation attenuation and thus the more challenging it becomes.”

Extending the distance that useful millimeter-wave signals travel opens up possibilities for wireless providers. “Network operators will have the potential to use their existing mobile network assets to deliver fixed wireless services,” the Australia-trial group said. These might include delivering broadband internet access to buildings.