在物聯網環境下低功耗藍牙技術廣泛應用在家庭網路和個人移動場域，但當每個物件裝置均需藉由中央控制器角色來協助接取網路，會因為感測裝置位置不同或距離過遠而無法做到最佳消耗能量控制，若是其電源是依賴電池，則無法做到遠端和近端設備同時電源耗盡的目標，在內圈的感應器會因為要處理由外圈匯入的資料流，會較外圈的感應器有較快耗電的結果，形成內圈感應器較快電池耗盡，而形成網路路徑斷線，這對於管理感測裝置會造成通訊困擾。然而現今諸多的低功耗藍芽研究針對能源平衡之作法，為了達成功率消耗的平衡和考慮頻寬使用率，越靠近中央資料匯流點所需部署的感應器數越多，以便處理外層所入進的資料量，但是如此一來內層的感應器數量會暴增。 本篇論文提出一套適用於低功耗藍牙技術之傳送功率自動階層分級化機制，此機制可將所有感應器依據其位置，分成多個同心冕圈，並將一個傳送的頻寬分成若干等份，並允許內層使用較大頻寬比例，但越外層因為資料負載較輕，需使用頻寬相對較少，所以相對其內層功率消耗較少，這樣的設計可將內外層頻寬的使用差異量化，藉此找出其對應無線傳送功率的差異，並將此差異轉換成不同的傳送功率，以便讓較外層的感應器允許較遠的傳送距離。此外，外圈可藉由較大無線半徑，來消耗因頻寬使用較少所多出的功率，也可藉此提供較大無線覆蓋範圍，相較之下內圈則不需大範圍的無線覆蓋範圍，但須更高頻寬使用率來應付外圍資料流的匯入。再者本論文研究亦建置一套電流量測環境，根據低功耗藍芽感應器所在位置加以做發射功率控制以及封包最佳化，量測的模擬結果顯示，此機制可自動化分析內外層頻寬使用的分佈，進一步找出其每層頻寬功率差，並藉由調整天線傳送功率來消耗掉因頻寬使用率的差異，也可讓外圍感測裝置享有較遠的傳送距離，以達到內外層功率消耗相同的目標。相對於過去感測器均勻分佈和非均勻分佈機制的做法，我們提出的機制在對比感測器均勻分佈的做法有也減少百分之10的電池耗電速度，在對比以往均勻及非均勻分佈機制感測器無線所能覆蓋距離也有顯著的拉遠。因此，本論文提出的功率平衡機制應可適用在多數無線低功耗的環境/應用，期能達到延長整體無線網路使用時間以及增大無線感測計覆蓋的距離。 ;Bluetooth Low Energy (BLE) technologies are popular in IoT environments. Lots of BLE-enabled sensor devices must access the Internet by a central controller. Different sensor devices will cause different speeds of energy dissipation due to different sensor positions and distances. Thus, those devices cannot synchronize power drains simultaneously between distal and proximal sensors. Current energy leveling techniques are apt to deploy an increasing number of sensors closer to the central sink of data flows to process the increasing amount of data from outer regions, this manner which aims to strike a balance of power consumption and bandwidth utilization. However, this sort of techniques can induce a considerable increase of sensor devices and induce unscaled cost expense for sensor deployment in a large application field. This paper proposes a balancing mechanism for power dissipation in BLE-based wireless sensor networks. The mechanism design is to divide the positions of all sensors into m coronas, and the bandwidth of a transmission can be divided into k basins. Sensors in an inner corona use a larger portion of transmission bandwidth, while data loading in an outer corona is relatively less. Thus, the proposed mechanism can differentiate the usages of transmission bandwidth between inner and outer coronas. With the information of differentiated data load and bandwidth usage, this mechanism can specify different transmission powers and convert the difference into separate transmission distances. Particularly, sensors in an outer corona can consume higher power using a larger wireless radius, and also provide a larger range of wireless coverage. By contrast, the inner circle does not require a wide range of wireless coverage, but requires higher bandwidth to cope with the convergence of incoming data streams from other outer areas. Finally, the simulation results show that adjusting the antenna transmission power and controlling the bandwidth usage can obtain the goal. Those sensors in both inner and outer areas can have similar power consumptions.
