Chapter 2: Interrogation Zone Basics
RFID+ Exam Objectives Covered in this Chapter:
| ü | 1.1 Describe interrogator functionality
|
| ü | 1.2 Describe configuration of interrogation zones
|
| ü | 1.3 Define anticollision protocols (e.g., number of tags in the field/response time) |
| ü | 1.4 Given a scenario, solve dense interrogator environment issues (domestic/international)
|
Interrogation zones, despite their name, are not zones for interrogating criminals-unless these criminals carry a radio frequency identification (RFID) tag. An interrogation zone, also called a read zone, is an area specially configured for reading information from or writing information to RFID tags. Interrogation zones can consist of various hardware components, but the main devices that make these zones work are RFID interrogators with antennas connected to them. The rest of the equipment is optional, but is useful for either mounting the interrogators and antennas (such as different types of portals, racks, and stands) or adding capabilities to the zone via various peripheral devices such as RFID printers/encoders, light stacks, and motion sensors.
In this chapter, you will discover the components of an RFID interrogator as well as the interrogator's functions. You will learn that interrogators are capable of reading tags and writing information to tags; they can directly manage various input/output (I/O) devices and offer a graphical user interface (GUI) for easy configuration. You will see that interrogators can be updated through firmware upgrades and you will learn when it is appropriate to upload a new firmware version.
Next, I will show you the difference between a "dumb" reader and a "smart" reader as well as the capabilities that a smart reader can provide. You will also learn about various communication methods between readers and tags and restrictions posed on the radiated power that vary by region. Then you will go through techniques of tag population management that consist of several interrogator commands including the always popular Kill command (this chapter will be very morbid).
You will also learn about the various types of interrogators, such as fixed interrogators and mobile interrogators including vehicle-mounted interrogators, handhelds, and other kinds of mobile devices, as well as their functions, installation, and suitable applications.
After you learn the basics about interrogator construction, functions, and types, you will dive into factors that affect the performance of an interrogation zone. You will learn about the dwell time necessary for successful reading and/or writing operations, as well as various aspects of antenna performance. You will identify types of antenna polarization, such as linear or circular polarization, and antenna design, where you will learn about differences between bi-static and mono-static antennas. Next, you will understand the antenna coverage as well as its imperfections, and how the field changes with power input. You will learn about antenna configurations in the form of RFID portals and tunnels as well as their function, suitable use, and customization according to your environment and applications. You will also learn about antenna tuning and proper shielding in order to prevent RF interference.
You will then identify the dense reader environment and its challenges. You will learn how to overcome these challenges by using synchronization, the listen-before-talk (LBT) technique, and frequency hopping. Because dense reader mode solves reader collisions, you will also have to find out what happens if two or more tags respond at the same time. This situation has to be handled by anticollision methods, and you will learn about the various types of these algorithms.
Finally, this chapter will give you a great overview of various factors and challenges related to interrogation zones and their components, as well as teach you about solutions to problems that can come up when designing, installing, or using the RFID interrogation zones.
EAN: N/A
Pages: 136