What is RFID Air Interface Communication Protocol?

ISO/IEC 18000-1 Information Technology: (Radio Frequency Identification Based on Item Management)Reference Structure and Standardized Parameter Definition . It regulates the communication parameter table of the reader and the tag, the basic rules of intellectual property rights, etc., which are commonly observed in the air interface communication protocol. In this way, the standards corresponding to each frequency band do not need to repeatedly specify the same content.

ISO/IEC 18000-2 Information Technology: (Radio Frequency Identification Based on Item Management) applicable to low frequency 125~134kHz, specifies the physical interface for communication between the tag and the reader, the reader should have Type A (FDX) and ability to communicate with Type B (HDX) tags; specifies protocols and commands plus anti-collision methods for multi-tag communication.

ISO/IEC 18000-3 Information Technology: (Radio Frequency Identification Based on Item Management) applicable to high frequency 13.56MHz, and specifies the physical interface, protocol and command between the reader and the tag plus anti-collision methods. Anti-collision protocol can be divided into two modes, among which, mode 1 is divided into basic type and two extended protocols (multi-response protocol without time slot and non-termination and time-slot termination adaptive polling multi-transponder reading protocol): Mode 2 adopts the time-frequency multiplexing FTDMA protocol, and a total of 8 channels are suitable for the situation with a large number of tags.

ISO/IEC 18000-4 Information Technology: (Radio Frequency Identification Based on Item Management) suitable for microwave band (although 2.4GHz is in the UHF frequency band, it is conventionally called the microwave band, for the same reason, 5.8GHz RFID should be in the SHF band, which is also counted in the microwave band) 2.45GHz, which specifies the physical interface, protocol and command between the reader and the tag, plus anti-collision methods. The standard includes two modes: Mode 1 is the working mode of passive tags, and the reader will talk first; Mode 2 is active tags, and the working mode is that the tag will talk first.

ISO/IEC 18000-6 Information Technology: (Radio Frequency Identification Based on Item Management) is applicable to the ultra-high frequency band 840~960MHz, and specifies the physical interface, protocol and command between the reader and the tag plus anti-collision methods. It contains 4 passive tag interface protocols of Type A, Type B, Type C and Type D, and the communication distance can reach up to 10m. Among them, Type C was drafted by EPC Global and approved in July 2006. It has greatly improved in terms of recognition speed, read and write speed, data capacity, anti-collision, information security, frequency band adaptability, and anti-interference. The V4.0 draft submitted in 2006 expands the characteristics of electronic tags with auxiliary power and sensors, including tag data storage methods and interactive commands. Active tags with batteries can provide a wider range of reading capabilities and greater communication reliability, but they are larger and more expensive.

ISO/IEC 18000-7 is suitable for ultra-high frequency band 433.92MHz,it belongs to active tags. Specifies the physical interface, protocols and commands between the reader and the tag plus anti-collision methods. Active tags have a wide reading range and are suitable for tracking large fixed assets.

Depending on the protocol, whoever speaks first between the reader and the tag is very different, and the Tag Talks First (TTF), Reader Talk First (RTF). The most common is RTF, and most RFIDs follow RTF: but there are also a few protocols that follow TTF, such as the 18000-6D protocol and the 18000-4 mode 2, which are all tags first, and the advantage of tags is the acquisition speed. It is fast, highly sensitive, and has strong real-time performance. At the same time, it has obvious shortcomings, such as small amount of transmitted data and simple functions.