“Green” is becoming a new wave in all the industries. The idea is to curb the negative impacts of human involvement. Efforts for “Green” has been put in all the product cycle shown in the figure above. Scientists are looking for new alternative energy source, and manufacturing and transportation companies are trying to improve the operation efficiency to reduce the energy consumption at factories and cars. New batteries have been studied to make devices last longer.
Our goal is to contribute in the third “Operation/Use” cycle by reducing the energy consumption at IT devices. The traditional cost function in the communication system design had been Signal-to-Interference-and-Noise-Ratio. Hence, the design criterion is changing from “How much throughput we can get” to “How much power we can save satisfying the minimum requirements of users,” as shown in the figure below.