  Future wireless cellular networks will utilize millimeter-wave and sub-THz
frequencies and deploy small-cell base stations to achieve data rates on the
order of hundreds of Gigabits per second per user. The move to sub-THz
frequencies will require attention to sustainability and reduction of power
whenever possible to reduce the carbon footprint while maintaining adequate
battery life for the massive number of resource-constrained devices to be
deployed. This article analyzes power consumption of future wireless networks
using a new metric, the power waste factor ($ W $), which shows promise for the
study and development of "green G" - green technology for future wireless
networks. Using $ W $, power efficiency can be considered by quantifying the
power wasted by all devices on a signal path in a cascade. We then show that
the consumption efficiency factor ($CEF$), defined as the ratio of the maximum
data rate achieved to the total power consumed, is a novel and powerful measure
of power efficiency that shows less energy per bit is expended as the cell size
shrinks and carrier frequency and channel bandwidth increase. Our findings
offer a standard approach to calculating and comparing power consumption and
energy efficiency.
