| This paper studies the energy consumption of frame slotted Aloha (FSA) based anti-collision protocols. Specifically, we investigate twelve FSA variants using a detailed qualitative and quantitative methodology to evaluate their energy efficiency with varying tag population. Our results show that the variant that adjusts its frame size in accordance with tag population and incorporates the muting and early-end feature has the lowest energy consumption, hence most suited for RFID-enhanced WSNs. |