A new dynamic frame slotted ALOHA algorithm based on collision factor

In order to solve the problem of the tag collision in RFID system, this chapter presents a new dynamic frame slotted ALOHA algorithm based on collision factor according to the previous different kinds of ALOHA algorithms. By introducing the pretest groups of number and collision factor, the tag number estimating method settles the severe collision where all the slots are collided slots in a frame while most of algorithms do not resolve this problem. Simulated results on MATLAB show that the estimated number of tags with this new algorithm is accurate, and the efficiency of this new algorithm is higher than other algorithms especially on the severe collision condition. On the basis of guaranteeing the accuracy of tags estimation, the problem of severe collision that the number of empty slots and readable slot are both zero was solved by the method proposed in this chapter, which ensures high speed of identification. In all, this algorithm has good performance both when there is severe collision and under normal condition.