ANTI-COLLISION PROCEDURE - ANTI-COLLISION

ANTI-COLLISION PROCEDURE - ANTI-COLLISION - DEFINITION

The anti-collision procedure is also known as the multi-access procedure or simply anti-collision.
Anti-collision describes a set of procedures that enable tags to communicate simultaneously. This is intended to prevent the overlapping of several different signals. The anti-collision procedure regulates the sequence and spacing of responses. This is achieved, for example, by randomly distributing the transmission of these responses so that the receiver can read each tag individually. The performance of the anti-collision procedure is measured in ‘tags/s’. There are four basic types of anti-collision procedures.

4 TYPES OF ANTI-COLLISION PROCEDURES

• Space Division Multiple Access (SDMA): Spacing, range, antenna type and positioning are set
• Time Division Multiple Access (TDMA): Access time is divided between participants
• Frequency Division Multiple Access (FDMA): Different frequencies are used
• Code Division Multiple Access (CDMA)
  

ANTI-COLLISION PROCEDURES IN THE RFID FIELD

In the field of RFID technology, the following anti-collision methods are typically used:

• Slotted ALOHA: a variant of the ALOHA method from the 1970s (Aloha Networks, Hawaii). Aloha was the inspiration for the Ethernet protocol and is a TDMA method.
• Adaptive Binary Tree: Here, a binary search is used to find a specific tag in a mass.
• Slotted Terminal Adaptive Collection (STAC): is very similar to the ALOHA method, but is considerably more complex.
  EPC UHF Class I Gen 2: is a singulation method.