Solar-powered cell phone access point for cell phone users in emerging regions

The availability of electrical power is a critical issue for building sustainable communication networks in emerging regions. Low-cost energy delivery encourages people to use communication services. This paper presents simulation results on the effect of the distribution of the surplus power generated for an access point (AP) to cell phone users. We show that 9.3% of the user population can use the excess power generated for the AP. Furthermore, we propose an energy-proportional server cluster to ensure computational resources for information services, such as for charging cell phones. The existing server hardware often wastes power in the idle state and is not energy proportional, and thus we designed the cluster to reduce this energy waste by matching the number of working servers to the number of incoming requests. Our prototype system with low-power and off-the-shelf devices cuts energy consumption in the frequently observed idle state by 50% compared with an existing server cluster with equivalent performance.