An Investigation into the Energy Efficiency of Pure and Slotted Aloha Based RFID Anti-Collision Protocols

This paper investigates the energy efficiency of RFID anti-collision protocols and their suitability for use in RFID-enhanced wireless sensor networks (WSNs). We present a detailed analytical methodology and an in-depth qualitative and quantitative energy consumption analysis of Pure and Slotted Aloha anti-collision protocols and their variants. We find that Slotted Aloha variants that employ muting with early-end are the most energy efficient, but are computationally expensive. Overall, for all Aloha variants we investigated, if the offered load is very high, tag responses cause a bottleneck at the reader. Thereby, resulting in no tags being identified and incur significant identification delays – thus severely impacting a sensor node’s battery life.