無線感測網路（wireless sensor network, WSN）是由多個感測節點所組成的一個無線區域型網路架構，是一套可應用在各種不同環境的無線感測應用，例如：健康監控、商業使用、農業環境、家庭或工業自動化等區域型的網路環境。為了滿足前述應用需求，需建置大量的感測節點散佈於各處，因此感測節點就需具備低功耗、低成本、短距離傳輸之能力實現大量部署需求。
為了實現上述的需求，IEEE提出一套IEEE 802.15.4標準滿足前述所說之環境應用。在標準中，是採用超碼框（superframe）架構來進行資料傳輸。在競爭存取週期時，感測節點利用載波檢測多重存取與碰撞避免（carrier sense multiple access with collision avoidance, CSMA-CA）機制來傳輸資料，但此種方式會因感測節點數量增加或網路負載情形增加時，提高感測節點間碰撞機率，降低網路效能；另外，標準定義了免競爭週期的保證時槽（guaranteed time slot, GTS），來服務固定頻寬需求以及時間急迫性的資料傳輸，此種方式則在節點數量增加、負載增加時，能因避免碰撞問題，而有較佳的網路效能。
就目前的相關研究來看，皆針對競爭存取週期來進行探討，且透過協調者所收集到的資訊，進行超碼框架構的調整，來提升網路效能，但此種調整方式最終還是受到載波檢測多重存取與碰撞避免機制在網路負載以及感測節點數量增加的情況下，有調整超碼框架構的極限。而若利用免競爭週期的保證時槽機制，將不受載波檢測多重存取與碰撞避免機制的影響，只要感測節點取得時槽利用的許可後，即可將資料傳送出去，提升整體網路效能。
因此，為了實現上述環境，本論文提出一個整合保證時槽之適應性超碼框調整機制（Adjustment Scheme for Adapted Superframe with Guaranteed Time Slot, ASGTS），利用競爭存取週期低負載情況，有高傳輸的能力，以及免競爭週期高負載情況，能避免碰撞機會產生的特性，再根據協調者收集到的資訊，適應性地超碼框的長度，提升網路效能。從模擬結果可發現，本論文提出的機制，在有效產能上比IEEE 802.15.4標準及先前提出的機制有較好的表現。

Wireless sensor network (WSN) is a wireless area network architecture composed of multiple sensing nodes. It is a set of wireless sensing applications that can be used in various environments, such as health monitoring, commercial use, agricultural environment, home or industrial automation and other regional network environment. In order to meet the needs of the application, need to build a large number of sensing nodes scattered everywhere, so the sensor nodes need to have the capacity of low power, low cost and short distance transmission to achieve a large number of deployment needs.
IEEE proposed a set of IEEE 802.15.4 standards to meet the aforementioned environmental applications. In the standard, it uses superframe structure for data transmission. In the contention access period, the sensing node uses carrier sense multiple access with collision avoidance (CSMA-CA) mechanism to transmit data, but this mechanism will raise the probability of collision between sensing nodes and reduce network performance because of the number of sensing nodes or the network load increased. In addition, the standard defines the contention-free period, it uses guaranteed time slot (GTS) to serve the fixed bandwidth requirements and the urgency of the data transmission. This mechanism can avoid collision problems and have better network performance when increasing the number of sensing nodes and the network load increases.
In the view of current researches are discussed about the contention access period, and through the information collected by the coordinator to adjust the superframe to improve the network performance. But these adjustments will be affected by the CSMA-CA mechanism, which reduces network performance when the number of sensing nodes increases or the network load increases. However, if the guaranteed time slot mechanism is used, it will not be affected by the CSMA-CA mechanism. As long as the sensing node obtains the permission of the slot, the data can be transmitted and enhance overall network performance.
In order to fulfill the above-mentioned environment, this paper proposes an Adjustment Scheme for Adapted Superframe with Guaranteed Time Slot (ASGTS). With the low network load condition of the contention access period, it has the capability of high transmission, As well as the contention-free period of high network load conditions, to avoid the collision opportunities arising from the characteristics, and then according to the information collected by the coordinator, adaptively over the length of the superframe to improve network performance. From the simulation results can be found that the mechanism proposed in this paper has a better performance on goodput than the IEEE 802.15.4 standard and the previously proposed mechanism.

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