多穿戴式裝置於短距無線傳輸之輪詢設計

Abstract

近幾年來，由於人們對個人健康照護與運動的重視，越來越多的穿戴式裝置出現在市場上，許多相應的應用也為改變人們的生活而生。然而，當這麼多穿戴式裝置同時被運用時，一個重要的技術課題是如何讓這些裝置即使遭遇不同應用而有不同的記憶體限制、封包與資料傳輸速率，而仍然在現有的短距無線通訊技術下確保所有裝置的封包都能在延遲上限內抵達。 本論文中，我們討論以智慧手持裝置作為所有穿戴式配備連網核心的網路架構。我們希望可以藉由針對穿戴式身軀區域網路下封包週期性抵達的特質，修改既有的輪詢系統分析與設計輪詢的序列來解決相關的服務品質(QoS)問題。我們提出了一個相應於此網路的系統模型並謹慎的進行系統分析，並探討實作此系統的四個主要部分: 通訊型態通訊裝置的硬體實作、藍芽通訊協定在硬體的實現方式、通訊型態通訊裝置的作業系統以及行動裝置上的應用程式實作方法。以上這些觀念、分析、方法和設定在本論文中均予以詳細討論。另外，我們也會呈現每個部分的測試結果。 本論文提出一個名為通用輪詢設計(GPSD)的演算法並簡易的在Android裝置上實作了一個基礎的輪詢模型。通用輪詢設計包含三個主要的部分: 系統檢查、找到所有優質的序列並找出符合需求的候選者以及序列選擇。系統檢查針對裝置的組合檢查了所有的穩定度條件以及其他基本的系統要求。完成這些檢查項目後，手持裝置可以開始尋找所有可能優質序列並確認其中可以符合所有裝置延遲限制之序列。手持裝置再選擇一個對最高優先保護的裝置是有最高延遲保障的序列來確保最需要被保護的裝置不會遺失封包。最後本論文經由模擬分析，驗證同一演算法，在不同情境下與不同演算法的一般設定做比較。由分析結果得知，本論文提出的演算法可以有效的改善使用者體驗並讓使用者可同時的使用更多裝置。並且，此演算法的實作是簡易且可行的。

As demands for personal healthcare and workout training grow, a huge number of wearable devices have come to the market in recent years. Many devices and applications have been designed and developed to change the way people live. Services which didn’t exist in the past seem to be available and are discussed lively. One of the important issue is how to guarantee the delay requirements of devices when they are having different buffer limits, packet size, and data rates, using short range wireless communications. In this thesis, we focus on the network architecture with a smart handheld as center of wearable devices collecting sensing data in a wireless wearable body area network. We aim to solve related QoS problems by refining the polling model under periodic processes and designing a polling sequence for given devices. We propose a system model for the network and made careful analyses on this architecture, including hardware architecture on MTC devices, introduction of Bluetooth protocol stack, operating system on MTC devices and implementation methods on mobile central devices. The concept, analyses, methods and setup in this thesis will be described, and testing results of each component are demonstrated. II We proposed an algorithm called General Polling Sequence Design (GPSD) and implemented a related basic model of it on Android devices. GPSD contains three main parts: System Checking, Finding of Possible Sequences and Candidates, and Sequence Selecting. The System Checking checks the stability condition and other basic system limit for given devices. After this checking, the handheld can start the Finding of Possible Sequences and Candidates and know that whether there is a sequence satisfies all delay requirements for devices. The handheld can then select one sequence with highest delay tolerance for high-priority device among them to make sure its packet will not be dropped. The proposed algorithm, GPSD, was validated and evaluated under several scenarios via simulations. We also compared the results with the default systems. By simulation results, GPDS could improve user experiences and accommodates more devices and services. Moreover, the implementation of it can be easy.