1、逢甲大學資訊工程學系碩士班碩士文一個 RFID 第一第二代標籤之可調適反碰撞演算法 An Adaptive Anti-Collision Algorithm for RFID Class 1 Generation 2 Tags 指導教授：黃秋煌研究生：郭聖邦中華民國九十七八月 中文摘要 RFID技術在未勢必被廣泛的運用，如醫、軍事、商業活動等。但此科技本身也擁有著少嚴重的問題，如安全性問題、隱私權問題、訊號碰撞問題。RFID系統裝置是透過無線電波進資交換，因此是同時有多個裝置發出無線電波，將會造成訊號碰撞，以致於其它裝置無法取到正確資訊。訊號碰撞一般可分為取器訊號碰撞以及電子標籤訊號碰撞大，取
2、器訊號碰撞指的是同一個電子標籤同時收到多個取器所發出的訊號，電子標籤訊號碰撞指的是同一台取器同時收到多個電子標籤所發出的訊號。依照 Class 1 Generation 2 的規定，取器以及電子標籤傳遞訊息所使用的頻同，因此碰撞只會由取器和取器所發出的訊號互相碰撞產生，稱為取器碰撞；或是電子標籤和電子標籤所發出的訊號相互碰撞產生，稱為電子標籤碰撞。 而本篇文主要是探討電子標籤訊號碰撞問題。先討改變各種反碰撞演算法之所帶的弊，再依照其弊，分析每種反碰撞演算法適用的情況。最後綜合上述結，實做出一套可調適的反碰撞演算法，在同的情況，做出同的調整，達到較好的效。 關鍵詞: 無線射頻辨、取器、電子標籤、
3、反碰撞、走訪樹、Aloha反碰撞演算法、EPCGlobal網、第一第二代 iAbstract Radio frequency identification (RFID) technology has been extensively used in various application domains, such as medical management, military affairs, retail business, em etc. There are several serious problems with the RFID technology, for instance,
4、the problems of security, privacy and the signal collision. An RFID system includes two kinds of device, interrogator and tag, exchanging information through radio wave. Radio transmission will cause signal collision when there are too many devices transmitting signal at the same time. Usually, two
5、types of collision are considered: interrogator collision and tag collision. Interrogator collision means that one tag receives more than one signal sent simultaneously by interrogators; tag collision means that one interrogator receives more than one signal sent simultaneously by tags. There are ma
6、inly two types of anti-collision algorithms used to resolve signal collisions. One is tree-based anti-collision algorithm and another one is Aloha-based anti-collision algorithm. Tree-based anti-collision algorithms classified tags into several different sets by translating a sequence of masks until
7、 each set contains only one tag. Aloha-based anti-collision algorithms used time-slicing skill, making tags respond in different time to avoid signal collision. This paper mainly discusses the problems of tag collision. We design an adaptive anti-collision algorithm which uses historical tag informa
8、tion and implement the algorithm with EPC C1 Gen2 commands. This adaptive anti-collision algorithm can determine whether the historical tag information is suitable for inventory or not. Interrogator employs this algorithm to query tag with historical tag information if historical tag information is
9、suitable for inventory tags and abandon historical tag information if it is not suitable. The adaptive algorithm achieves better performance than traditional tag anti-collision algorithm. iiKeywords: RFID, reader, tag, anti-collision, tree-walk, Aloha, EPCGlobal C1 Gen2 iiiContents 中文摘要i Abstractii
10、Contents.iv List of Figures.vi List of Tablesvii 1 Introduction.1 2 Related Work. 6 2.1 Aloha algorithm6 2.2 Tree Walk algorithm.8 2.3 Class-1 Generation-210 2.3.1 Tag.10 2.3.2 Interrogator11 2.3.3 Commands of Class-1 Generation-2.11 2.4 Implement of Tree Walk and Aloha Using EPC C1 Gen2 Command15 2
11、.4.1 Tree Walk Anti-Collision Algorithm.15 2.4.2 Aloha Anti-Collision Algorithm16 2.5 Compare Tree Walk with Aloha.17 3 Methodology.18 3.1 Performance of anti-collision algorithm18 3.2 Related Math model.24 4 Adaptive Anti-Collision Algorithm.26 4.1 Adaptive Anti-Collision Algorithm26 4.2 Class-1 Ge
12、neration-2 Simulator.26 4.3 Implementation of each algorithm in simulator.29 iv4.3.1 Implementation of Tree Walk Algorithm in Simulator29 4.3.2 Implementation of Aloha Algorithm in Simulator32 4.3.3 Implementation of Adaptive anti-collision algorithm in simulator.34 5 Performance analysis.35 6 Concl
13、usions.38 vList of Figures 2.1 State diagram of Aloha anti-collision algorithm7 2.2 State diagram of Tree Walk anti-collision algorithm.9 3.1 Performance of aloha algorithm using method 1.19 3.2 Performance of aloha algorithm using method 2.20 3.3 Performance of aloha algorithm using method 3.21 3.4
14、 Performance of aloha algorithm using method 4.22 3.5 Performance of Tree Walk algorithm.23 3.6 Performances of the four Tree Walk based algorithms24 4.1 Structure of adaptive anti-collision algorithm28 4.2 Class-1 Generation-2 command generator for Tree Walk30 4.3 C1 Gen2 command generator for Aloh
15、a anti-collision algorithm32 4.4 EPC C1 Gen2 command generator for Adaptive anti-collision algorithm.34 5.1 Performance of case 136 5.2 Performance of case 236 5.3 Performance of case 336 5.4 Performance of case 437viList of Tables 1.1 Application types of RFID system.2 1.2 Application type and ISO
16、Standard.3 1.3 The ability of electronic tag and its class level3 4.1 Structure of adaptive anti-collision algorithm27 4.2 Resource using in each step27 4.3 Main Classes of simulator and its capability29 4.4 Behavior of Tree Walk using C1 Gen2 simulator31 4.5 Behavior of Aloha using C1 Gen2 simulator.33 vii
