在IEEE 802.15.4 beacon-enabled無線個人區域網路中，網路協調者 (PAN coordinator) 使用GTSs (guaranteed the time slots ;保證時槽) 配置免競爭的slots給admitted devices。但是admitted devices沒有使用完配置的slots，這會造成bandwidth waste。文獻 [6] 指出slot size導致頻寬浪費問題，這是由於superframe結構的先天缺陷。於是文獻 [6] 提出multi-beacon superframe structure (簡稱MBS) 去克服這個問題。然而MBS的superframe structure對於資料的處理缺乏彈性。因此，本篇論文提出改良式多重信標超級訊框結構(簡稱EMBS)。EMBS能夠動態調整superframe structure，其中superframe中可以根據admitted devices所需傳輸的資料大小而包含各種不同型態的sub-beacon intervals (簡稱SBIs)，因而使得頻寬浪費的問題得到緩解。為了增強效能，本論文還提出一個貪婪配置SBIs演算法。模擬結果顯示，使用EMBS的無線個人區域網路會比使用802.15.4和MBS協定有較高的bandwidth使用率。

In an IEEE802.15.4 beacon-enabled wireless personal area network (WPAN), the PAN coordinator can allocate slots using contention free-GTSs (guaranteed the time slots) for admitted devices. However, due to fixed slot size, the bandwidth waste problem may arise. Hence, reference [6] proposed the multi-beacon superframe structure (MBS) to overcome this problem. However, in [6], the structure of sub-beacon intervals in a superframe is non-adaptive. Therefore, this thesis proposes an enhanced multi-beacon superframe structure (EMBS). In EMBS, a PAN coordinator employs the greedy SBI-allocation algorithm to adjust a superframe structure according to the traffic demand of admitted devices such that a superframe can consist of a number of different types of sub-beacon intervals (SBIs). Simulation results reveal that a WPAN using EMBS can attain higher bandwidth utilization than a WPAN using 802.15.4 or MBS.

第一章 緒論 1
1.1 簡介 1
1.2 Superframe Structure 1
1.3 資料傳輸過程 3
1.4 由Slot大小所引起的Bandwidth Waste問題 4
1.5 論文貢獻 5
1.6 論文架構 6
第二章 相關文獻 7
第三章 The Proposed Protocol 10
3.1 Network Model and Assumption 10
3.1.1 Superframe可供配置的Time Slot個數 10
3.1.2 EMBS的Superframe架構 11
3.1.3 Superframe配置基本單位 12
3.1.4 Admission Control 12
3.2 Problem Definition 12
3.3 Protocol Overview 13
3.4 Protocol Detail Description 13
3.4.1 統計data frame對於sloti的需求 13
3.4.2 查表法 14
3.4.3 例外處理 19
3.5 EMBS演算法 21
3.6 EMBS範例 24
第四章 模擬實驗 26
4.1 實驗參數設定 26
4.2 Beacon的影響 27
4.3 Devices完成傳輸時間 31
4.4 EMBS的Superframe結構變化 33
4.5 Bandwidth Waste的比較 34
第五章 結論 36
參考文獻 37

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[7] A. Koubaa, M. Alves, and E. Tovar, “I-GAME: An Implicit GTS Allocation Mechanism in IEEE802.15.4 for Time-Sensitive Wireless Sensor Networks,” 18th Euromicro Conference on Real Time Systems, July 2006.
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[8] S.-T. Sheu, Y.-Y. Shih, and L.-W. Chen, “An Adaptive Interleaving Access Scheme (IAS) for IEEE 802.15.4 WPANs,” IEEE Vehicular Technology Conference Spring, pp. 1523-1527 Vol. 3, May 2005.