iPTT：VoIP系統之點對點即按即說服務

Abstract

本論文提出一個VoIP系統上之點對點即按即說服務，稱之為iPTT。在iPTT上，我們展示了一個分散式並且不受限於行動通訊業者之網路架構，以加速PTT服務之推廣。基於我們提出的架構，我們也設計了通話建立及結束的訊息流程以展現iPTT架構的可行性。此外，我們提出兩種即時發話權決定機制，分別為Flooding-based Floor Control Mechanism (FFC) 與Tree-based Floor Control Mechanism (TFC)。對於所提出的發話權決定機制，透過我們所發展的數學分析與模擬模型來評估其效能。而其效能之優劣取決於決定過程所需的時間與訊息數量。

This thesis proposes iPTT, a peer-to-peer Push-to-Talk (PTT) service for Voice over IP (VoIP). In iPTT, a distributed and mobile-operator independent network architecture is presented to accelerate the deployment of the PTT service. Based on the proposed architecture, the message flows for call establishment/teardown are designed to show the feasibility of iPTT. Also, we propose two mechanisms for real-time talk-burst determination, flooding-based floor control mechanism (FFC) and tree-based floor control mechanism (TFC). In terms of the determination latency and the number of floor-control message exchanges, the performance of the proposed floor control mechanisms is investigated through our analytical and simulation models.