We mix the results of the two phones as well as download
and upload scenarios since they are similar.
We make three key observations. First, Bundling consumes less
energy compared with LTE-only, despite turning on the extra WiFi
radio. This is because Bundling improves the transfer throughput
so that the transfer ends earlier. As a result, the energy saving due
to reduced transmission time compensates the extra power draw
of the WiFi radio. To further illustrate this, we plot in Figure 8
Bundling’s energy cost as a function of its throughput gain (inverse
of the throughput ratio RX defined in §5). We see that in general
the energy cost scales inversely with the throughput gain.