Engineering solutions take time to surface as real-world applications. The common reason for their delayed adaption is the technical challenges and complexities. While RFID as a technology is very simplistic and convenient for the end-user, there is also one technical aspect that the solution architects must consider for their system.
What Is RFID Reader Collision?
RFID reader collision happens when two different readers are placed within the RFID range; thus, the collision occurs. In simpler words, it is a phenomenon where two readers can read each other, interfering with the tag reading. To learn more about this phenomenon, it is essential to understand how the communication between multiple readers and tags works.
LBT system- Listen Before Talk
Conventional RFID solutions used an LBT system where the reader would first verify if there were any other traffic on the channel. Then, the reader would only transmit the RF if there were no other traffic. Finally, the tag would use that same channel to revert following that RF signal. The limitation here was that only one reader could exist within the range of a particular channel.
The issue here is that if there are two readers nearby operating on the same channel, the chances are that both can interfere with each other’s tag reading in that area. In addition, as the RFID tags do not have any channel selectivity, those tags will revert to the channel from which they are receiving the power. Therefore, only one of the readers can read the tag at a particular time, the one with higher signal strength.
This is one of the common scenarios for warehouses and similar RFID implementations where multiple fixed and handheld readers are used simultaneously.
LBT’s successor: DRM (Dense Reading Mode)
A dense reading environment refers to an environment with multiple readers in the same area. With Dense Reading Mode, RFID can overcome the limitations of LBT by using separate channels for readers and tags. Readers were allowed four high-power channels, while tags could respond on free channels between those high-power signals. By implementing the DRM channel plan, the reader doesn’t have to verify other traffic on the channel before transmitting. Multiple readers can operate in the same zone, and tags have a different set of frequencies to revert to the readers.
It is essential to ensure that multiple readers are placed in the same zone to perfect this solution architecture. The direction and pattern of the reader antennas determine efficient isolation between both the readers. As long as different reader antennas are not facing each other, the reading of the tags does not have to be sequential.
Need a hand in perfecting your RFID implementation?
It can be a bit tricky to watch out and prepare for these unique occurrences. However, with an expert by your side, you can pick the right hardware and installation for your RFID solution. Feel free to reach out to us with your application for RFID, and we will propose to you the best RFID reader & tag solution that you need.
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HF+UHF Dual-Band RFID Reader / Writer AZ-R1
This is a high-performance reader/writer with both HF and UHF reading capabilities and supports a variety of protocol standards, such as ISO 18000-6C, ISO 14443 A/B, and ISO 15693. With excellent HF and UHF reading performance, it can achieve UHF tag reading at rapid velocity and maintain a high recognition rate simultaneously. Besides, it is easy to deploy and operate by connecting its USB port to a PC without driver installation. All these make it widely used in various RFID applications such as logistics, access control, anti-counterfeiting, and production process control.
