Story 2016-11-13

Does millimeter wave cellular broadband offer rural applications?

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A New York University (NYU) student research team pushed the envelope for millimeter wave network range in a recently conducted field test in rural southwest Virginia. Setting up a millimeter wave transmitter on the porch of the country home of their professor Ted Rappaport, the students found that they could receive signals at distances of over 10 km (6.2 mi) even when line of sight was obstructed by a hill or a stand of trees. Equally significant, the millimeter wave transmitter needed less than 1 watt (W) of power operating at 73 GHz.

The FCC in June opened 11 GHz of new spectrum in the millimeter wave band to network operators for the development of 5G technology. The results of the NYU student research team's field trial bode well for prospective carrier-grade applications, particularly regarding using existing cellular telecom infrastructure to provide 5G broadband services in underserved rural areas, according to Prof. Rappaport. The results could broaden industry participants' and regulators' perspectives regarding the use of millimeter wave technology

Others disagree with that conclusion. University of California, San Diego professor of electrical and computer engineering Gabriel Rebeiz pointed out that the field trial was conducted over two days when the skies were clear. Previous research has found that rain can reduce millimeter wave signal strength at a rate of 20 decibels per kilometer, the equivalent of nearly 100-fold per kilometer. Despite its potential in urban areas, Rebeiz still believes proposing to use millimeter wave technology in rural areas is a non-starter.