Studies on design and development of energy-aware middleware for mobile terminals

在视频流播放中，便携式无线设备需要大量的电能用于视频数据解码和无线通信。因此，需要控制功耗，以便将电池寿命延长到理想的播放持续时间和/或将指定百分比的电池容量留给其他应用。在这项研究中，我们提出了一个电池感知视频流系统，考虑到每个用户指定的视频质量偏好和便携式无线设备的剩余电池量，可以在指定的时间内播放。该系统通过视频转码和视频数据的周期性批量传输来降低功耗。我们已经在PDA和笔记本电脑上实现了该系统，并进行了一些实验。结果，我们已经确认，我们的系统可以将电池寿命延长到PDA的2.8倍，笔记本电脑的1.6倍，并且可以以相当小的误差控制电池寿命。

In streaming playback of video, portable wireless devices consume a lot of electric power for video data decoding and wireless communication. Therefore there are demands to control the power consumption so that the battery life can be extended to a desirable playback duration and/or the specified percentage of the battery capacity is left for the other applications. In this research, we have proposed a battery-aware video streaming system to play back for specified duration considering a preference of quality of video specified by each user and the remaining battery amount for portable wireless devices. In the system, power consumption is reduced by using transcoding of video and periodic bulk transfer of video data. We have implemented the system and carried out several experiments using a PDA and a laptop PC. As a result, we have confirmed that our system can extend the battery life up to 2.8 times on the PDA and up to 1.6 times on the laptop PC, and can control the battery life with reasonably small error.