一個以Binary Tree架構為基礎的RFID辨識機制

Abstract

RFID是近年來所發展出來的一套無線射頻辨識系統，它被廣泛地使用在物流作業上，並且漸漸地取代傳統的Bar Code來辨識貨品，透過被附著在貨品上的RFID標籤，利用無線電波的傳輸方式，RFID標籤的ID Code被Reader所讀取。在RFID的標準中，標籤和Reader的辨識方式主要是以Binary Tree辨識模式為基礎，然而Binary Tree辨識模式在標籤數量較多的環境下，辨識過程較為冗長，所需花費的時間較多，主要的原因是當標籤數量增多的時候Reader和標籤的總溝通次數會快速地增加，如果在多標籤的辨識環境下，減少標籤和Reader之間的溝通次數將是最重要的課題。在此，本論文嘗試採用一種以Binary Tree辨識模式為基礎的新式辨識機制，來試圖減少原本在Binary Tree辨識模式中Reader和標籤在辨識過程中總共所需的溝通次數，以藉此縮短Reader在辨識過程中所需耗費的時間以及所需的電力。 模擬的過程中，主要是根據標籤的長度、標籤的數量、標籤ID Code的相似度以及使用的記憶體數量這四個變因來分析原本的Binary Tree辨識模式和本論文所提出的辨識機制在標籤的總回應次數和Reader的總查詢次數的差異，以及改善的程度比例。由模擬實驗結果觀之，在標籤位元長度愈長、標籤數量愈多以及標籤ID Code的相似度愈高的情況下，本論文所提出的辨識機制能夠有效地降低辨識過程中的總溝通次數，而降低的幅度平均大約在十五到六十個百分點左右。

RFID is one kind of identification system developed in recent years. It was used in the distribution operation broadly and replaced traditional Bar Code to identify products gradually. The RFID tags attached to products are read by RFID reader using radio transmission. According to the standard of RFID，the identification mode between the tags and reader is based on Binary Tree Identification Scheme mainly. However，the process of Binary Tree Identification Scheme is copious when the tags are numerous , and it takes much time. The root cause is that the communication times between the reader and tags will increase rapidly when the tags are more and more. To decrease the communication times between the reader and tags will be the most important course in the multi-tags environments. According above，this paper attempted to propose a novel identification scheme based on Binary Tree Identification Scheme to reduce the total communication times between the reader and tags. So that it can shorten the time and save the power in the identification process. In the simulation process，this paper analyzed the difference of the tag response times、reader inquiring times and improved ratio between the BT scheme and improved scheme according to four aspects：tag bit-length、the number of tag、the similarity of tags’ ID Code and the amount of memory used. According to the simulation results，the novel scheme this paper proposed can reduce the total communication times. And the average decrease of the communication times reaches fifteen to sixty percentages.