In order to compare different technologies, we measured
also the case when streaming over 3G with the same phone
(HSPA in Figure 7). There is a notable difference in the average
current when streaming directly from the server in favor
of HSPA but the difference becomes negligible if cDRX is
activated. The figure includes also the current draw caused
by listening FM radio with the same smartphone. Although
the energy savings can be cut by more than half with traffic
shaping and cDRX, the resulting current is still double the
plain old radio. We measured similarly the FM radio current
of N900 and the result was the same 100 mA than with
the LTE phone. However, the lowest average currents we
measured for audio streaming over 3G are only marginally
higher than the average FM radio current.