A New Optimization Criteria For Frame Slotted ALOHA Utilizing Time And The Collision Recovery Coefficients

Abstract:
Minimizing the reading time of the tag population is a critical issue in the RFID systems. The usual approach to reduce the reading time is to select the frame size attaining the highest throughput in the frame. Previous studies have focused on the conventional frame length calculations. In such a systems, they assume equal slot durations and only the single tag reply is considered as a successful slot, and if multiple tags respond simultaneously, a collision occurs, then all the replied tags are discarded. However, the modern system have two main capabilities: a) The readers can identify the slot type and hence optimize the slot duration. b) The readers have collision recovery capability, which means the ability to convert the collided slot into a successful slot. In this work we propose a novel reading efficiency metric taking into consideration the effect of the collision recovery probabilities and the time differences in the slots durations. Timing comparisons are presented in the simulation results to show the saving in reading time using the proposed frame length compared to the other proposals.