Analysis of DFSA anti-collision protocols in passive RFID environments

Frame slotted Aloha (FSA) protocols are promising anti-collision protocols for passive RFID systems. They aim at decreasing the time to detect all the tags in range (identification delay). In FSA, the maximum identification rate (average number of tags identified per slot) is achieved when the number of contending tags matches the cycle length (number of slots in a frame). Therefore, the reader should ideally know the actual number of competing tags. However, in RFID scenarios this figure varies randomly, and the reader has to guess the number of contenders somehow. This paper analyzes the most relevant anti-collision algorithms; taking into account the limitations imposed by the world-wide de-facto standard EPCglobal Class-1 Gen-2 for passive RFID systems.