The cable industry, Arris, and CableLabs have been doing some testing of the proposed G5 frequency spectrum. The test result outline some of the challenges broadband providers face in deploying 5G services, including dealing with trees and other foliage.
One of the highlights of living in rural Sierra counties is the plethora of trees that surround our homes and businesses. These trees we enjoy provide some real line of sight (LOS) deployment challenges for 5G providers. How significant are these challenges? According to the report, the problems are substantial for those providers using millimeter-wave distribution systems. AT&T and Verizon have spent billions to acquire millimeter spectrum and are planning to use that spectrum for G5 broadband distribution.
In its 37 GHz tests, CableLabs found that speeds decreased to around 200 Mbps at 150 feet if signals have to travel through foliage – and those figures slow to below 100 Mbps at 150 feet in dense foliage.
Rain, snow, and wind can dramatically reduce the effectiveness of millimeter wave transmissions. “The impact of deciduous and conifer trees (under gusty wind conditions) suggest that the leaf density from the conifer more frequently produces heavy link losses and these, more so at higher carrier frequencies,”
So far we have only looked at foliage impacts. The Sierra landscape is one of hills and valleys. That rolling terrain makes the line of sight communication extremely difficult. While the top of a hill can be good distribution points, the next hill across the valley creates a shadow for the millimeter wave signal. Also, millimeter-wave beamforming antenna has some distance limitations measured in feet. The distance from hilltop to the end user in a rural setting will often exceed those limitations. Millimeter-wave distribution is better suited to urban environments were the transmission devices and be placed on light poles and other existing infrastructure close to the end user.
In the tree covered hill and valleys of the Sierra Whitespace TV proposed by Microsoft offer some advantages over 5G millimeter-wave distribution. As the report concludes:
We have come a long way in the drive to 5G — but as the saying goes — there is still a long way to go.
Note: The cable industry report discusses many complex details not covered in this short report on foliage and terrain impacts on 5G distribution in the Sierra and deserves a complete and detailed read by community broadband advocates and those opposed to G5 implementation. The full report: 2017-can-a-fixed-wireless-last-100m-connection-really-compete-with-a-wired-connection-.