Radio Frequency Identification is an Automatic Identification Technology. RFID system typically consists of a reader and a number of tags. When more than one tag send signal to reader at the same time, reader will not identify any one. This is called collision. The information of collision is regarded as uselessness in the conventional algorithms. But in fact, useful information can be extracted from the collision and the reading efficiency can be improved. In this paper, tags use BIBD(16,4,1) blocks instead of RN16, the reader analyses the collision information based on the characteristics of BIBD and makes valid recognition even when more than one tag have been detected in same time slot. The theoretical and simulation results show that the proposed algorithm can improve the reading efficiency by 100% than that of the conventional Q algorithm. Furthermore, the proposed scheme changes little to the existing standard, easy to implement and compatible for EPC Global Code.
