Yong-Ju Jang

Battery-aware wireless video transmission based on battery recovery effect

This paper proposes a battery-aware wireless video transmission where video coding bitrate is intentionally lowered than transmission channel bitrate. Battery lifetime significantly improves by shutting down transceiver and giving idle time to battery, at the cost of image quality degradation. Measurement shows effective battery lifetime increases to 2~3 times at the PSNR degradation of 0.25 dB.

Low-Power 32bit×32bit multiplier design with pipelined block-wise shutdown

This paper proposes a novel low-power 32bit×32bit multiplier with pipelined block-wise shutdown scheme. When it idles, it turns off supply voltage to reduce both dynamic and static power. It shutdowns and wakes up sequentially along with pipeline stage to avoid power line noise. In idle mode, the proposed multiplier consumes 0.013mW and 0.006mW in 0.13μm and 0.09μm technologies, respectively, and it reduces power consumption to 0.07%~0.08% of active mode. As fabrication technology becomes small, power efficiency degrades in the conventional clock gating scheme, but the proposed multiplier does not. The low-power design methodology in this paper can be easily adopted in most functional blocks with pipeline architecture.

Battery lifetime and PSNR quality-scalable video transmission for mobile multimedia systems

A battery lifetime and PSNR quality-scalable video transmission is proposed. Video bitstream is intentionally encoded at lowered bitrate, and it is intermittently transmitted to exploit battery recovery effect. Battery lifetime is extended significantly with PSNR quality degradation given by user. Both battery lifetime and PSNR quality are precisely estimated and easily controlled by adjusting encoding bitrate and battery duty ratio. Battery lifetime extension is fully scalable with PSNR quality degradation, and vice versa. Measured battery lifetime was extended up to 31.4 times at the cost of 1.20∼3.89 dB PSNR degradation in H.264 video coding and ZigBee transceiver. Absolute average errors of estimated PSNR degradation and battery lifetime were less than 7.31%.