Parallel Response Ternary Query Tree for RFID Tag Anti-Collision

Ching-Nung Yang,Li-Zhe Sun,Song-Ruei Cai

doi:10.4236/jcc.2015.35009

Ching-Nung Yang, Li-Zhe Sun + Show 1 more

Open Access

https://doi.org/10.4236/jcc.2015.35009

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Abstract

A tag-collision (or missed reads) in RFID system (Radio Frequency Identification) system degrades the identification efficiency. The so-called tag collision is that a reader cannot identify a tag when more than one tags respond to a reader at the same time. There are some major anti-collision protocols on resolving tag collision, e.g., ALOHA-based protocol, binary tree protocol, and Query Tree (QT) protocol. Up to date, most tag anti-collision protocols are QT protocols. QT protocols are categorized into M-ary query tree (QT). In the previous literature, choosing M = 3 (i.e., a ternary QT (TQT)) was proven to have the optimum performance for tag identification. Recently, Yeh et al. used parallel response approach to reduce the number of collisions. In this paper, we combine the partial response and TQT to propose an effective parallel response TQT (PRTQT) protocol. Simulation results reveal that our PRTQT outperforms Yeh et al.’s protocol and TQT protocol.

Highlights

Radio frequency identification (RFID) system consists of readers, tags and backend database server [1]
Yeh et al [15] proposed a parallel response query tree scheme that combines the frequency shift keying (FSK) modulation and Manchester coding to provide two subcarriers for tags communicating with reader in parallel
We use a more complex reader that could distinguish three responded signals with different frequencies from tags, and meantime process each response in parallel. Notations and their descriptions used in the proposed parallel response ternary QT (TQT) (PRTQT) protocol are defined below

Summary

Introduction

Radio frequency identification (RFID) system consists of readers, tags and backend database server [1]. Yeh et al [15] proposed a parallel response query tree scheme that combines the frequency shift keying (FSK) modulation and Manchester coding to provide two subcarriers for tags communicating with reader in parallel. In this paper we adopt the parallel subcarriers of Yeh’s protocol and the optimal performance of TQT protocol to design a parallel response ternary query tree (PRTQT) protocol. The responded bits of tags are encoded as Manchester code, in which a low-to-high transition stands for 0, and a high-to-low transition stands for 1, as shown in Figure 1(a) and Figure 1(b) By this parallel two subcarrier responding and partial parallel prefix matching, Yeh et al.’s protocol performs like 4-ary QT protocol. Reader continuously sends the query string S = (0010) This procedure is repeated until all tags are successfully identified. We do not need to turn covert all EPC at once, and just convert the part we use

The Proposed PRTQT Protocol

Performance Evaluation

Conclusion