The effect of multiple simultaneous flows in the sensor
network is investigated next, with random selection of source
and destination nodes, while the number of flows is varied
from 1 to 6. Again, we observe the behavior of RF-MAC on
two energy and throughput metrics, when nodes experience
different levels of channel usage and traffic loads. Fig. 9 shows a
smooth and monotonic increase in the average harvested energy
of RF-MAC-opt as the number of flows increases. Even though
the RF-MAC-no-opt exhibits a similar pattern, the increase is
not as smooth as one with the frequency optimization. Evidently,
the amount of average harvested energy yield could
be almost 150% less than RF-MAC-opt. Fig. 10 depicts the
average network throughput of RF-MAC with various numbers
of data flows. Interestingly, the average network throughput
of both RF-MAC variants gracefully drops as the number of