非信標模式之IEEE 802.15.4效能分析

Performance Analysis on Non-beacon-enabled Mode IEEE 802.15.4

莊惟凱(Wei-Kai Chuang)

指導教授 ： 周俊廷

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.10678

摘要

ZigBee及IEEE 802.15.4提供無線個人化網路一套從網路層到實體層完整的通訊協定，其特性為低功率消耗及低傳輸速率，特別適用於電池裝置以及無線感知網路。協定中定義了基礎架構以及非基礎架構兩種拓樸分別支援不同種應用。另外依照訊框的形式又定義出兩種架構：信標支援、非信標支援。其中的差異在於各裝置之間是否有時間上的同步。
在此論文中，我們建立了一套數學分析模型針對基礎架構下使用非信標支援的訊框。我們引入了通道可用評估臨限值(Clear Channel Assessment Threshold)到我們的數學模型中。現存的研究並沒有針對此參數的影響作出分析。最終我們可以得知我們分析的結果與模擬的結果相當符合。於本論文的後段，我們更進一步討論一個特殊的案例並將我們的模型導入其中。
接下來，多跳網路的容量分析也被納入本篇論文。我們建立了模型以分析最大的空間利用率。由此最大空間利用率，我們可以進而推算出最大的多跳網路容量。在本論文中，我們使用行動容量來做為衡量標準。接著我們使用OPNET模擬飽和多跳ZigBee網路作為參考，並將其結果與分析結果相比較。可以得知，我們所提出的行動容量上限值為一相對逼近之上限。

關鍵字

非信標 IEEE 802.15.4 ； 多跳網路容量分析 ； 通道可用評估 ； 行動容量分析

並列摘要

ZigBee and IEEE 802.15.4 provide a low power solution from the network layer to the physical layer for battery-equipped devices with relaxed requirement on data rate in wireless personal area networks (WPANs). The solution provides both infrastructure and infrastructure-free network topologies, namely the star and mesh. Beacon-enabled mode and non-beacon-enabled mode are also de ned to support synchronous and asynchronous transmissions.
In this thesis, we focus on building a mathematical model for the star topology with devices transmitting data to the coordinator in the non-beacon-enabled mode. We include a clear channel assessment (CCA) threshold into the analysis which is new from other existing researches. The proposed analytical model captures the behaviors of the system precisely, and the analysis matches well with our simulations. We further discuss a speci c scenario and implement our model as a case study.
Moreover, the capacity analysis of a multi-hop network is also conducted in this thesis. We build a model to obtain the maximum spatial reusability so as to achieve the performance upper bound of the network. Transport capacity is used as an metric to evaluate the performance of the network. We then implement a saturated ZigBee mesh network by OPNET Modeler as an example to examine the capacity upper
bound we proposed.

並列關鍵字

non-beacon IEEE 802.15.4 analysis ； un-slotted IEEE 802.15.4 ； multi-hop networks capacity ； ZigBee analysis ； transport capacity ； CCA threshold

參考文獻

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