The design of sustainable wireless sensor network node using solar energy and Phase Change Memory

Sustainability of wireless sensor network (WSN) is crucial to its economy and efficiency. While previous works have focused on solving the energy source limitation through solar energy harvesting, we reveal in this paper that sensor node's lifespan could also be limited by memory wear-out and battery cycle life. We propose a sustainable sensor node design that takes all three limiting factors into consideration. Our design uses Phase Change Memory (PCM) to solve Flash memory's endurance issue. By leveraging PCM's adjustable write width, we propose a low-cost, fine-grained load tuning technique that allows the sensor node to match current MPP of solar panel and reduces the number of discharge/charge cycles on battery. Our modeling and experiments show that our sustainable sensor node design can achieve on average 5.1 years of node lifetime, more than 2× over the baseline.