Anti-collision algorithms in RFID systems
Speaker: Majid Al-Otaibi, ITEE
When: 2007-12-11 10:00:00
Venue: 78-622
Host: Dr Adam Postula
Abstract:Radio frequency identification (RFID) is a contactless, without
line-of-sight, low-power and low-cost wireless communication technology that
provides automatic identification and data collection. In addition, RFID can
read multiple tags simultaneously and work in harsh environments.
The signals in both directions between the reader and the tag may collide
because reader and tags communicate over a shared wireless channel. As a
consequence, either the reader may not identify all tags or a tag
identification process may suffer from long delay. Thus, anti-collision
algorithms which provide quick and correct recognition regardless of the
occurrence of collisions are required.
Tag anti-collision algorithms can be classified into two broad groups:
probabilistic algorithms and deterministic algorithms. Probabilistic
anti-collision algorithms in RFID systems provide simple implementation and
good performance for small amount of tags. However, they suffer from a
serious problem called tag starvation problem. This problem occurs when a
specific tag is not identified for a long time. On the other hand,
deterministic anti-collision algorithms in RFID systems achieve full read
rate. Although they have relatively long identification delay, they do not
cause the tag starvation problem.
Combining two algorithms from both categories benefits from their advantages
and solves their problems. Using deterministic anti-collision algorithm
avoids the tag starvation problem and fulfils 100% read rate. Furthermore,
probabilistic anti-collision algorithm reduces the delay caused by the
deterministic algorithm. Therefore, the main focus of this study is to take
the advantages of both algorithms.
Based on the literature review, a good tag anti-collision algorithm for RFID
systems ought to have the following characteristics. First, a reader should
recognize all the tags inside its own interrogation zone. The tag starvation
problem causes the failure of object tracking and monitoring. Since the
reader, however, cannot estimate the number of tags accurately, the
guarantee of identifying all tags should be taken into consideration in the
design of the tag anti-collision algorithm. Second, a reader should
recognize tags promptly. Since an object with a tag is totally mobile, tag
identification must correspond with the object’s velocity. If tag
identification runs slower than the object’s velocity, the reader cannot
identify it and the RFID system fails in monitoring or tracking. Finally, a
tag must be identified while consuming a small amount of resource. Since the
tag has low computational capability, limited memory, and limited power, the
tag anti-collision algorithm must load the tag with the least possible
communication and computation overheads. To achieve high performance with
the proposed tag anti-collision algorithm, it should meet the
characteristics which are mentioned above.
Biography:(biography unavailable)
Type: Ph.D confirmation
Contact:Dr Adam Postula, seminar host (adam@itee.uq.edu.au)
or Guido Governatori (ITEE seminar co-ordinator)
(guido@itee.uq.edu.au)