We observe that the device remains at the high power
mode (CELL_DCH) if the 10-second segmentation is used,
since the state transition takes at least 30 seconds, as given
in Section V-A. On the other hand, using 60-second burst
transmission intervals, CloudMoV may transfer the device to
the low power mode (IDLE) via the intermediate power mode
(CELL_FACH) from time to time. In this way, CloudMoV
can achieve approximately 29.1% power saving. We also
observe some unexpected behavior of the power levels around
400 seconds, where the power does not drop. After checking
Tomcat server logs on the VM surrogate, we find that the device
requested the play list file (.m3u8) twice around that time,
possibly due to packet loss, and the tiny traffic of the playlist
(about 4 KB) deprived the device from a “sleep” chance.