[Back]

M. Bueno Delgado, C. Angerer, J. Vales Alonso, M. Rupp:
"Estimation of the Tag Population with Physical Layer Collision Recovery";
Talk: The Third International EURASIP Workshop on RFID Technology (RFID 2010), La Manga del Mar Menor, Cartagena, Spain; 09-06-2010 - 09-07-2010; in: "Third International EURASIP Workshop on RFID Technology", (2010), 106 - 111.

In passive RFID systems, tags are arbitrated on
the Medium Access Control layer by the Framed Slotted Aloha
protocol. Tags select an arbitrary slot to send their information,
such that the reader receives slots with no responses, single tag
responses or multiple tag responses, generating empty, singleton
and collision slots, respectively. In order to maximize the system
throughput, precise knowledge of the tag population competing in
the read range of the reader is required. Normally, a reader does
not have that information and needs to estimate it in every identification
round from the statistical information collected: empty, singleton
and collision slots. However, this estimate is poor since conventional
readers are not capable of determining how many tags
actually respond simultaneously when a collision slot occurs. In
this work, we use a physical layer reader architectures to extract
the exact number of tags participating in a collision. We employ
this additional information and a technique that permits to successfully
extract tag signals from collision slots. This establishes a
much more accurate Maximum Likelihood estimator which outperforms
other estimators studied in depth in previous works.

estimation, tag population, RFID, collision recovery, collision resolution, receiver, reader, multiple tags, signal separation, framed slotted aloha, physical layer

http://publik.tuwien.ac.at/files/PubDat_187764.pdf

Project Head Christoph Mecklenbräuker:
Christian Doppler Lab "Funktechnologien für nachhaltige Mobilität"