The diffusion of cellphone and landline phone

We investigate the problem of family energy consumption in the process of replacing landline phones with cell phones. We found that cell phones consume much less energy than landline phones. We adopted U.S as our study samples. We applied Gompertz function to predict the cell phone diffusion trend in the U.S and hence simulate energy consumption by family phones during this process. Our results indicate that the transition stage will end at 2011, while energy consumption by phones declines monotonously during this period.