Ultra-high frequency tag decoding device supporting error correction

Abstract

The present invention provides a UHF tag decoding device supporting error correction, which is characterized by comprising: a ternary counter, a carry counter, a PIE counter, and an error correction symbol decision maker. When a PIE symbol is received, the ternary counter and the PIE counter start counting. When the count value of the ternary counter is 2, the carry counter is incremented by 1. After the PIE symbol ends, the error correction symbol decision maker performs error correction based on the count values of the ternary counter, the carry counter, and the PIE counter, and determines whether the current PIE symbol is 0 or 1 according to the corrected value. The beneficial effect of the present invention is that when the decoding clock frequency is relatively low and the Tari length is relatively short, the problem of misjudgment of the traditional decoding method can be solved.

Description

Technical Field

[0001] The present invention belongs to the field of integrated circuit design, and more specifically, to the technical field of ultra-high frequency RFID tag chip decoding. Background Art

[0002] RFID (Radio Frequency Identification), namely radio frequency identification technology. A set of radio frequency identification system generally consists of a reader, an electronic tag and a back-end data processing platform.

[0003] According to the frequency of the radio signal sent by the reader, the RFID system can be divided into four types: low frequency, high frequency, ultra-high frequency and microwave. Among them, the ultra-high frequency RFID system based on the EPC Class1 Gen2 protocol has a working frequency of 860MHz - 960MHz, and is applied to scenarios with longer reading and writing distances and higher reading and writing speeds.

[0004] It is stipulated in the EPC Class1 Gen2 protocol that the data sent by the reader to the tag uses PIE coding. How to reduce the decoding clock frequency and reduce the possibility of misjudgment during decoding has always been a research hotspot.

[0005] As shown in the appendix Figure 1 , according to the protocol regulations, the PIE symbol length of logic 0 is equal to 1 Tari. The PIE symbol length of logic 1 is greater than or equal to 1.5 Tari and less than or equal to 2 Tari. The PIE symbol length of RTCAL is greater than or equal to 2.5 Tari and less than or equal to 3 Tari. The PIE symbol length of TRCAL is greater than or equal to 2.75 Tari and less than or equal to 9 Tari.

[0006] Currently, the popular method for PIE coding and decoding is to count Tari and RTCAL sent by the reader as a whole. After dividing the count value by 3, the rounded result is recorded as N. Then count the subsequent PIE symbol lengths. When the symbol length after RTCAL is greater than 2N, it is judged as TRCAL. When the symbol length is greater than or equal to N, it is judged as logic 1. When the symbol length is less than N, it is judged as logic 0. Compared with the previous traditional method, this method can reduce the decoding clock frequency, but the disadvantage is that when the decoding clock frequency is relatively low and the Tari length is relatively short, using this method for decoding may still have the problem of misjudgment, resulting in decoding failure. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the present invention proposes an ultra-high frequency tag decoding device supporting error correction. It is characterized by including: a ternary counter, a carry counter, a PIE counter, and an error correction symbol decision maker.

[0008] The main function of the ternary counter is to count according to the ternary rule. Whenever the count reaches 2, the counter returns to 0 and starts counting again. The input of the ternary counter is connected to the output data of the analog module demodulation, and its output is connected to the input of the carry counter.

[0009] The main function of the carry counter is to increment by 1 whenever the ternary counter counts to 2. The input of the carry counter is connected to the output of the ternary counter, and its output is connected to the input of the error correction symbol decision device.

[0010] The main function of the PIE counter is to count the length of each PIE symbol and store the final count value. The input of the PIE counter is connected to the output data of the analog module demodulation, and the output is connected to the input of the error correction symbol decision device.

[0011] The main function of the error correction symbol decision device is to perform error correction on the count values of the ternary counter and the carry counter, and then compare the corrected value with the value of the PIE counter to determine whether the current PIE symbol is 0 or 1. The input of the error correction symbol decision device is divided into three paths. One path input is the output of the ternary counter, one path input is the output of the carry counter, and the other path input is the output of the PIE counter. Its output is the decoded output data, which is output for use by other functional modules.

[0012] The beneficial effect of using the present invention is that when the decoding clock frequency is relatively low and the Tari length is relatively short, using this device for decoding can effectively solve the problem of misjudgment caused by using traditional methods. Description of the Drawings

[0013] Figure 1 is the PIE coding format specified by the protocol.

[0014] Figure 2 is the ultra-high frequency tag decoding device supporting error correction proposed by the present invention. Detailed Embodiment

[0015] The following specifically describes the preferred embodiments of this device according to the drawings.

[0016] As Figure 2 shown, the ultra-high frequency tag decoding device supporting error correction includes: a ternary counter, a carry counter, a PIE counter, and an error correction symbol decision device.

[0017] The ternary counter has its input connected to the demodulated output data of the RF circuit and its output connected to the inputs of the carry counter and the error correction symbol decision maker. The ternary counter performs ternary counting. Whenever the count reaches 2, the value of the counter is cleared to 0 and the cumulative counting restarts. When a PIE symbol ends, the ternary counter stores its current count value.

[0018] The carry counter has its input connected to the output of the ternary counter and its output connected to the input of the error correction symbol decision maker. Whenever the ternary counter counts to 2, the carry counter increments by 1. When a PIE symbol ends, the carry counter stores its current count value.

[0019] The PIE counter has its input connected to the RF demodulated output data and its output connected to the input of the error correction symbol decision maker. Whenever a PIE symbol is received, the PIE counter starts counting. When a PIE symbol ends, the PIE counter stores its current count value.

[0020] The error correction symbol decision maker has its inputs respectively connected to the outputs of the ternary counter, the carry counter and the PIE counter, and its output is the decision output data. When a PIE symbol ends, the error correction symbol decision maker first compares the value of the PIE counter with the value of the carry counter. When the value of the PIE counter is greater than the value of the carry counter, this PIE symbol is decided as 1. When the value of the PIE counter is less than the value of the carry counter, this PIE symbol is decided as 0. When the value of the PIE counter is equal to the value of the carry counter, correction needs to be made according to the value of the ternary counter. When the value of the ternary counter is 2, this PIE symbol is decided as 1. When the value of the ternary counter is 0 or 1, this PIE symbol is decided as 0.

[0021] It can be seen from the above embodiments that the beneficial effect of the present invention is that when the frequency of the decoding clock is relatively low and the length of Tari is relatively short, it is very likely to cause misjudgment by using the traditional rounding method, but the present invention can perform effective error correction to avoid the occurrence of misjudgment.

[0022] Although the content of the present invention has been introduced in detail through the above preferred embodiments, after those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. The above description and drawings are only examples of implementing the present invention, but it should be recognized that the above description should not be considered as a limitation to the present invention.

Claims

1. An ultra-high frequency tag decoding device supporting error correction, characterized in that, Including: a ternary counter, a carry counter, a PIE counter, and an error correction symbol decision maker; For the said ternary counter, when receiving a PIE symbol, the ternary counter starts counting. Whenever it counts to 2, the counter is cleared to 0 and starts cumulative counting again; When the PIE symbol ends, the ternary counter stops counting and stores its count value. For the said carry counter, when the said ternary counter counts to 2, the value of the carry counter is incremented by 1. When the PIE symbol ends, it stores its count value; For the said PIE counter, when receiving a PIE symbol, the PIE counter starts counting. When the PIE symbol ends, the PIE counter stops counting and stores its current count value; For the said error correction symbol decision maker, its inputs are respectively connected to the outputs of the ternary counter, the carry counter, and the PIE counter, and its output is the decision output data. When a PIE symbol ends, the error correction symbol decision maker will first compare the values of the PIE counter and the carry counter. When the value of the PIE counter is greater than the value of the carry counter, this PIE symbol is decided as 1. When the value of the PIE counter is less than the value of the carry counter, this PIE symbol is decided as 0. When the value of the PIE counter is equal to the value of the carry counter, correction needs to be made according to the value of the said ternary counter. When the value of the said ternary counter is 2, this PIE symbol is decided as 1. When the value of the said ternary counter is 0 or 1, this PIE symbol is decided as 0.

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