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.
This paper proposes a modification to the existing anticollision protocol put forth in version 1.0 protocol specification for 900MHz Class 0 RFID Tag. The version 1.0 specification uses a binary tree approach to singulate one RF tag ID at a time. The proposed change reduces the overall read time of a given number of RFID tags by resetting to the appropriate node, for every consecutive read cycle. The present standard resets to the root node of the binary tree for every read cycle. This paper presents an efficient collision resolution protocol and its variations for the tag identification problem, where an electromagnetic reader attempts to obtain within is read range the unique ID number of each tag. The novelty of our main protocol is that each tag is memoryless , i.e., the current response of each tag only depends on the current query of the reader but not on the past history of the reader's queries. Moreover, the only computation required for each tag is to match its ID against the binary string in the query. Theoretical resulst in both time and communication complexities are derived to demonstrate the efficiency of our protocols.