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1 Overview of RFID System Anti-Collision Technology
maximum serial number, so the tag transponder sends its serial number back
to the reader at the same time.
(2) Due to the uniqueness of the tag sequence number, when the number of tags
is not less than two, the system will inevitably collide. In case of collision, the
reader will set the corresponding starting position of collision in the maximum
sequence number to 0, and the position lower than that will remain unchanged.
(3) The reader sends the processed start and low bits of the collision to the tag
transponder, which compares its sequence number with the value, equals the
value, and sends back the remaining bits of its sequence number.
(4) Loop through the above steps until a tag with the minimum sequence number
is selected. After the reader communicates normally with the tag, a command
is issued to put the transponder into hibernation, that is, it will not respond to
the reader request command unless it is reenergized.
(5) Repeat until each tag is identified in sequence from small to large.
1.2.3 Physical Anti-Collision
In addition to using algorithms to avoid tag collisions, the book also proposes new
ideas for reducing tag collisions through physical methods. Here are four ways to do
this.
(1) Optimal geometric distribution of RFID multi-tag based on Fisher information
matrix
Using software algorithm can only prevent tag collision, but can not improve the
system’s reading performance. The Fisher information matrix contains information
such as the position and detection value of each tag. By analyzing and calculating
the determinant of the Fisher information matrix, the relationship between the tag
geometric distribution and the reader can be obtained to obtain the optimal geometric
distribution of the multi-tag system. Fisher information matrix is introduced to study
the location distribution of RFID tags, and then the optimal geometric arrangement
of tags can effectively improve the dynamic performance of the multi-tag system and
reduce the reading error.
(2) A method to enhance the system’s ability to read multiple tags by adjusting
the antenna design
All antennas (except the ideal point source antenna) radiate directionally in space.
By changing the antenna manufacturing technology, changing the antenna aspect
ratio, increasing the antenna downdip Angle, and so on, adjusting the antenna’s
direction and resonance frequency can effectively improve the system’s performance
in multi-tag reading.
1 Overview of RFID System Anti-Collision Technology
maximum serial number, so the tag transponder sends its serial number back
to the reader at the same time.
(2) Due to the uniqueness of the tag sequence number, when the number of tags
is not less than two, the system will inevitably collide. In case of collision, the
reader will set the corresponding starting position of collision in the maximum
sequence number to 0, and the position lower than that will remain unchanged.
(3) The reader sends the processed start and low bits of the collision to the tag
transponder, which compares its sequence number with the value, equals the
value, and sends back the remaining bits of its sequence number.
(4) Loop through the above steps until a tag with the minimum sequence number
is selected. After the reader communicates normally with the tag, a command
is issued to put the transponder into hibernation, that is, it will not respond to
the reader request command unless it is reenergized.
(5) Repeat until each tag is identified in sequence from small to large.
1.2.3 Physical Anti-Collision
In addition to using algorithms to avoid tag collisions, the book also proposes new
ideas for reducing tag collisions through physical methods. Here are four ways to do
this.
(1) Optimal geometric distribution of RFID multi-tag based on Fisher information
matrix
Using software algorithm can only prevent tag collision, but can not improve the
system’s reading performance. The Fisher information matrix contains information
such as the position and detection value of each tag. By analyzing and calculating
the determinant of the Fisher information matrix, the relationship between the tag
geometric distribution and the reader can be obtained to obtain the optimal geometric
distribution of the multi-tag system. Fisher information matrix is introduced to study
the location distribution of RFID tags, and then the optimal geometric arrangement
of tags can effectively improve the dynamic performance of the multi-tag system and
reduce the reading error.
(2) A method to enhance the system’s ability to read multiple tags by adjusting
the antenna design
All antennas (except the ideal point source antenna) radiate directionally in space.
By changing the antenna manufacturing technology, changing the antenna aspect
ratio, increasing the antenna downdip Angle, and so on, adjusting the antenna’s
direction and resonance frequency can effectively improve the system’s performance
in multi-tag reading.