A dynamic frame slotted ALOHA anti-collision algorithm for the internet of things

This paper proposes a novel anti-collision algorithm for passive RFID systems to be applied in the Internet of Things environments. The proposed algorithm is based on a Dynamic Frame Slotted ALOHA algorithm and is called NEDFSA. In the algorithm, tags are randomly assigned to time slots of a frame and when two or more tags collide in a slot, the collisions will be resolved by another DFSA algorithm while the other tags in the next slots will wait. The proposed algorithm uses an estimation mechanism to adjust the initial frame length to a value close to the number of tags, based on a power of two. The advantages of the proposal are that it retains the simplicity of DFSA, and its performance is not affected by the number of tags. Simulation results in ns-2 show that the efficiency of NEDFSA is up to 27% better than Q Algorithm. Also, the results show that the graphs plotting the efficiency of the algorithm are nearly horizontal when the number of tags increases from 100 to 1800, which confirms the high scalability of NEDFSA.