Radio Frequency IDentification (RFID) systems are becoming more and more popular in the field of ubiquitous computing, in particular for objects identification. An RFID system is composed by one or more readers and a number of tags. One of the main issues in an RFID network is the fast and reliable identification of all tags in the reader range. The reader issues some queries, and tags properly answer. Then, the reader must identify the tags from such answers. This is crucial for most applications. Since the transmission medium is shared, the typical problem to be faced is a MAC-like one, i.e. to avoid or limit the number of tags transmission collisions. We propose a protocol which, under some assumptions about transmission techniques, always achieves a 100 perfomance. It is based on a proper recursive splitting of the concurrent tags sets, until all tags have been identified. The other approaches present in literature have performances of about 42 in the average at most. The counterpart is a more sophisticated hardware to be deployed in the manufacture of low cost tags.
We propose the ALOHA-based Dynamic Framed Slotted ALOHA algorithm (DFSA) using proposed Tag Estimation Method (TEM) which estimates the number of tags around the reader. We describe the conventional Tag Estimation Method and Dynamic Slot Allocation (DSA), which is the method to dynamically allocate the frame size according to the number of tags. We compare the performance of the proposed DFSA algorithm with the conventional algorithms using simulation. According to the analysis, the proposed DFSA algorithm shows better performance than other conventional algorithms regardless of the number of tags because the proposed algorithm has lower complexity and better delay performance.  We propose two ALOHA-based Dynamic Framed Slotted ALOHA algorithms (DFSA) using tag estimation method (TEM), which estimates the number of tags around the reader, and dynamic slot allocation (DSA), which dynamically allocates the frame size for the number of tags. We compare the performance of the proposed DFSA with the conventional Framed Slotted ALOHA algorithm (FSA) using simulation. According to the analysis, two proposed DFSA algorithms show better performance than FSA algorithm regardless of the number of tags