  This paper introduces Waste Factor (W) and Waste Figure (WF) to assess power
efficiency in any multiple-input multiple-output (MIMO) or single-input
multiple-output (SIMO) or multiple-input single-output (MISO) cascaded
communication system. This paper builds upon the new theory of Waste Factor,
which systematically models added wasted power in any cascade for parallel
systems such as MISO, SIMO, and MIMO systems, which are prevalent in current
wireless networks. Here, we also show the advantage of W compared to
conventional metrics for quantifying and analyzing energy efficiency. This work
explores the utility of W in assessing energy efficiency in communication
channels, within Radio Access Networks (RANs).
