FERREIRA, H. P. A.; DE PAIVA ALMEIDA FERREIRA, HILLNER.; http://lattes.cnpq.br/0065349790513268; FERREIRA, Hillner de Paiva Almeida.
Abstract:
This thesis presents a study about the Dynamic Framed Slotted ALOHA (DFSA) anti-
collision algorithms applied to Radio Frequency Identification (RFID) systems that operate in
Ultra High Frequency (UHF) and use microchip and non-battery tags (passive tags). In this
context, the author develops a new method that operates on DFSA algorithms and accelerates
the performance of backlog estimators. Assuming a critical scenario where the number of tags
to be read is much larger than the total of transmission intervals initially provided by the
reader (called the initial frame), the proposed Double-Approximation (DA) method performs,
in addition to the tag estimates toward to the tags transmitting, a second approximation, which
systematically reduces the tags transmitting toward to the tag estimates. In the end, a more
accurate estimation for the total of unidentified tags is quickly obtained. Simulated results
show that DFSA algorithms using the DA method (called DA-DFSA algorithms) have higher
and more stable throughput (gains between 3.5% and 12.24%) and smaller amounts of
transmitted RFID signals (reductions between 15% and 43%) compared to the traditional
DFSA algorithms.