在被動式RFID系統中，如何減少標籤的碰撞以增進系統效能一直是重要的議題。其中一種熱門的演算法就是Framed Slotted ALOHA(FSA)以及其相關變形。但當標籤數目越增加，傳統的FSA的系統效能以及平均延遲時間會顯著變差。我們無法只是藉由無限制地增加時槽數來解決問題。本論文探討與比較各種現有的演算法，並且提出改進自Enhanced Dynamic Framed Slotted ALOHA(EDFSA)及Progressing Scanning(PS) algorithm的演算法，稱為Dynamic Grouping (DG)演算法。DG演算法將標籤依距離感應器的遠近來分組，以避免使用過多的總時槽數。此外，DG演算法藉由每次的掃描結果估算出標籤在空間的分佈情況，並以此調整分組的區塊，使每組的標籤數的預估能夠更加的接近實際的情形。不同於PS演算法，DG演算法不僅能應用於標籤平均分佈的環境，在常態分布的環境也能有良好的效能。

In passive RFID systems, how to reduce the collision among tags is an important issue at the medium access control layer. The Framed Slotted ALOHA and its variations are well-known anti-collision algorithms for RFID systems. However, when the Framed Slotted ALOHA is used, the system efficiency and the average time delay deteriorate rapidly when the total number of tags increases. On the other hand, the total number of slots in a frame can’t be infinity. In this thesis, we first compare existing anti-collision protocols and then propose a novel algorithm based on the Enhanced Dynamic Framed Slotted ALOHA (EDFSA) and the Progressing Scanning (PS) algorithm. The proposed algorithm is called Dynamic Grouping (DG). The DG algorithm partitions the RFID tags according to the distances from tags to the reader in order to avoid using too many slots in a frame. Inparticular, the DG algorithm estimates the spatial distribution of tags based on previous scanning results and then adjusts the partition accordingly. Unlike PS algorithm, the DG algorithm is applicable when the RFID tags are uniformly distributed or normally distributed.

誌謝 I
中文摘要 II
Abstract III
第一章 緒論 1
1.1 RFID簡介 1
1.2 相關演算法 3
1.2.1 Framed Slotted ALOHA Anti-collision Algorithms 3
1.2.2 Basic Framed Slotted ALOHA (BFSA) Algorithm 4
1.2.3 Dynamic Framed Slotted ALOHA (DFSA) Algorithm 5
1.2.4 Advanced Framed Slotted ALOHA (AFSA) Algorithm 6
1.2.5 Enhanced Dynamic Framed Slotted ALOHA (EDFSA) Algorithm 7
1.2.6 Progressing Scanning Algorithm 8
1.2.7 The Query-Tree Protocol 9
1.2.8 Energy-Aware Multislotted Anticollision Protocols 10
1.2.9 ABS 11
1.2.10 Single Resolution Blocking ABS and Pair Resolution Blocking ABS 13
1.3 文章導讀 15
第二章 方法和架構 16
2.1 Dynamic Grouping Algorithm 16
2.2 對應不同分佈情況 23
第三章 模擬結果與效能分析 24
3.1 模擬參數和環境設定 24
3.2 模擬結果 25
第四章 結論 38
參考文獻 39

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