EPC RF identity protocols gen-2 UHF RFID explains the signaling layer and logical requirements for devices that use passive-backscatter, ITF systems for communication. In ITF systems, the interrogator talks first and communicates with the tag at the 860 MHz to 960 MHz frequency range. This protocol also specifies logical operating procedures, policies, and commands between interrogator and tag.
EPC RF identity protocols gen-2 also represents addresses of tag memory, command codes of interrogator, and bit fields between interrogator as RFU (Reserved for future use). GS1 EPCglobal is denoting these RFU values for future extensibility.
It supports the logical air interface procedures that define the communication link parameters between interrogator and tag such as signaling layer, data-coding technology, collision arbitration algorithm, transmitting and receiving structure. In addition, it monitors tag authentication, interrogator authentication and mutual authentication between tag & interrogator.
ITF RFID systems contain two elements; interrogator/reader and tag/label. The interrogator sends RF modulating signal to the tag within the 860 MHz to 960 MHz frequency range. The purpose of sending a continuous-wave RF signal is to activate the tag due to its passive nature. The RF signal consists of both information and operating energy. After acquiring operating energy from the interrogator, the tag responds through backscattering phenomena in which it modulates the reflection coefficient of its antenna.
The flow of communication between interrogator and tag follows the half-duplex mode; only one component sends information and another component receives it and vice versa. Considering the ITF RFID system, the interrogator talks first, tag listens to that information, and this process repeats itself.
If telecommunication vendors and industrial associates need this protocol for their RF systems, the components (interrogators and tags) must comply with all the requirements and specifications mentioned in this protocol. Interrogator and tag must implement the compulsory commands, modulate and demodulate a mandatory set of electrical signals and conform to all the radio signals mentioned in this protocol. To work under this protocol, the interrogator and tag shall not implement any commands that conflict with this protocol.
EPC RF identity protocols gen-2 UHF RFID uses four types of commands;
- Mandatory Commands
Compliant interrogators and tags must support all the mandatory commands.
- Optional Commands
Compliant interrogators and tags may or may not support all the optional commands. However, if any interrogator or tag supports any of the optional commands, it shall be according to requirements mentioned in this protocol.
- Proprietary Commands
All the proprietary commands mentioned in this protocol are envisioned for the manufacturing process and must not be enabled in the field-deployed RFID systems.
- Custom Commands
Like proprietary commands, custom commands are also intended for manufacturing purposes. The interrogator shall comply with custom commands only after performing the following operations;
- Tag’s singulations
- Interpretation of the identification of the tag’s manufacturer mentioned in the tag’s TID memory