Enhancing tag identification in RFID systems using slotted non-persistent protocols

Tag identification and collision removal is the most critical issue which is limiting the performance of RFID systems. In this paper we test the performance of two classes of anti-collision protocols that is collision detection (pure Aloha and slotted Aloha) and collision avoidance (non-persistent CSMA and slotted non-persistent ISMA). To evaluate the performance of these classes of protocols we implement a simulation environment in MATLAB where we model single reader and multiple tags which run these protocols. We evaluate these protocols on the basis of two parameters i.e. tag throughput and collision rate. We found that the collision detection protocols suffer heavily due to packet collisions and results in reduced tag identifications. Whereas collision avoidance protocols reduce the collision among data packet due to carrier sense which increase the throughput. We evaluate the protocols in an environment where reader is not aware of the number of tags present in its interrogation zone. Also dense RFID environment is created to analyze collision removal property of these protocols.