Collision Resolution Protocol for Mobile RFID Tag Identification


Radio frequency identification (RFID) is a method to retrieve and store data using a radio channel. The system consists of tags and a reader. This tag is essentially a radio frequency circuit, a CPU, and a small memory with a unique identifier. Wireless connectivity allows for communicating and giving the system ability for tracking and managing objects in real time. RFID systems face the challenge of tag collision. Where one channel is being used between reading multiple tags there are collisions and the inability to respond to requests from the reader creates a failure in most systems.


A method comprising of controlling communications between tags and unknown tags using a frame structure provides a unique solution against collisions. The tags are essentially either known tags that the radio frequency reader has previously identified as being within an interrogation zone, or the unknown tags that the identifications reader has not identified in the interrogation zone. This invention advantageously uses a tag state machine that enables a tag to determine access information that allows the tag to communicate with the reader along with the other known tags, using collision free protocol.


This tag identification method is more efficient and improves the process of tag identification. The protocol for distinguishing known and unknown tags, create the ability for distinguishing tags and their purpose for communication. Unknown tags are restricted to communicate with the reader only at times set aside for this purpose. The frame structure creates an identification frame and grants the ability for known tags to have assigned time slot during which communication is granted with the reader. The use of collision resolution algorithms also aid in the collisions that occur. This proposed invention aids the speed at which unknown tags are identified.


Mobile Networks - Radio frequencies

Patent Status


Stage Of Development

8,305,194 8,872,632

Licensing Potential

Development partner,Commercial partner,Licensing

Licensing Status

Available for licensing.

Additional Info Please note, header image is purely illustrative. Source: Scott Lewis, Flickr, CC BY 2.0.
Patent Information:
Case ID: R8147
For Information, Contact:
Donna Tumminello
Assistant Director
State University of New York at Stony Brook
K. Wendy Tang
Jaewook Yu