GB/T 29768-2013Information technology - Radio frequency identification - Air interface protocol at 800/900 MHz (English PDF)

4.1 Symbols

fc - Channel center frequency;

4.2 Abbreviations

AK - Authentication key;

5.1 Communication interaction model

After the command is sent, the reader continues to send the unmodulated radio frequency carrier and listens to the response data pack from the tag.

5.2.1 General requirements

The reader uses TPP to encode baseband data. The reader shall support the DSB-ASK or SSB-ASK modulation method. The tag shall be able to demodulate the DSB-ASK and SSB-ASK modulation method.

The reader uses TPP to encode baseband data, uses DSB-ASK or SSB-ASK to modulate the radio frequency carrier, to send commands to one or more tags.

5.2.7 Data encoding

The reader uses the TPP as shown in Figure 4 to encode the baseband data.

5.2.8 Preamble

The forward-link shall use the preamble communication as shown in Figure 5.

The preamble consists of a separator, a calibration symbol, a calibration symbol.

The length tolerance of the separator is ±5%; the length tolerance of the calibration symbol 1 and the calibration symbol 2 are both ±1%.

6.1 Anti-collision mechanism

Multi-tag anti-collision uses the DDS-BT mechanism, as shown in Figure 15. In this mechanism, the initial value of the tag time slot counter is set to 0.The time slot counter is gradually adjusted according to subsequent commands. When the time slot counter is 0, the tag jumps from the Arbitrate state to the reply state and starts to respond to the reader.

6.2 Tag storage area structure

6.2.1 Overview

The storage of tags is divided into four logical storage areas. tag information area, coding area, security area, user area. Among them, the user area is an optional area. Each logical storage area contains one or more words, as shown in Figure 16.

6.2.2 Tag information area

00h ~ 07h in the tag information area store the assigned identifier in the tag TID.

The location above 08h in the tag information area stores other data except the assigned identifier.

6.2.5 User area

The user area stores user-defined information. The tag may have no user area, or the user area can be divided into several subareas according to actual needs, up to 16 subareas. The structure of the multi-user area division is as shown in Figure 20. Each user subarea can have a different access password.

6.4 Tag state

6.4.1 General requirements

Tags that support security authentication shall include 8 states. ready, arbitrate, reply, acknowledged, authentication, open, secured, killed; tags that do not support security authentication shall include 7 states. ready, arbitrate, reply, acknowledged, open, secured, killed.

6.5 Reader command set

6.5.1 General requirements

The command set of the reader is divided into two groups, namely the checking group command and the access group command. The command code is as shown in Table 8. The necessary commands are those commands that the reader and the tag shall support; optional commands are those that the reader and tag may support.

6.5.9 Reply error command

The tag shall execute the reply error command as shown in Table 18. Tags in the reply state and acknowledged state, after receiving the reply error command, jump to the arbitrate state without changing their checking flag. Tags in the authentication state, open state, security state, after receiving the reply error command, jump to ready state and do not change its checking flag. Tags in arbitrate state, after receiving the reply error command, keep the current state without changing their checking flag. Tags in the ready state and killed state do not respond to the error command.

6.7 Secure communication protocol

Tags that require secure communication can use the following secure communication protocols.

7.1 Summary of physical layer and media access control layer parameters

The physical layer and media access control layer parameters from the reader to the tag are as shown in Table 56. […]