行動通訊網路之國際漫遊(以下簡稱：漫遊)的信令傳遞方式，從早期的通信衛星發展至目前的海底纜線，都屬於高維護成本的電信基礎設施，導致漫遊通話費用成本居高不下。隨著行動通訊網路技術發展，無形中促使OTT（Over The Top）的應用逐漸廣泛，甚至取代原本漫遊通話模式。即便如此，漫遊通話節費產品依然盛行，其主要原因是OTT服務無法提供優於目前行動通訊網路所擁有的特性：高通話品質、高移動性以及通話雙方不受應用軟體或終端裝置型號之限制（如Line無法與微信互通）。 由於漫遊的話務必須透過本地端服務網路或國際合作營運商的協議路由，才能順利將信令送達受話方，如此的程序卻造成Tromboning和Triangular等路由問題，對營運商而言，無形中衍生國際營運商合作的路由接續費用等相關成本。為改善上述問題，本論文的研究方法在不增加電信核心網路元件的基礎架構上使用漫遊閘道，分流處理目前行動通訊網路之漫遊的信令傳遞。採用動態更新漫遊用戶資料機制，降低各電信核心網路元件的運算資源，使漫遊的話務能採用更直接的路徑方式進行路由。 本研究所提出的方法，根據數學理論推導驗證可以發現，漫遊路由成本，不論是路由所需經過的國家數、網路元件數以及營運商連結數等，都能有效降低。模擬實驗結果也顯示，本研究方法能有效降低漫遊呼叫接通的時間，並能提升行動通訊網路前端網路元件的運算效能。在避免Tromboning和Triangular等路由問題的同時，降低營運商的話務路由成本，進而降低漫遊通話費用，提升用戶對漫遊通話使用率，達成雙贏局面。 / The ways of transferring signaling of international roaming, abbreviated to roaming in the following, in mobile communication network evolve from satellite communications, submarine cable communications, etc. The huge maintenance cost of telecommunication infrastructure results in high charge of a roaming call. Through the advancement of mobile communication network technologies, the emergent Over The Top (OTT) applications had been widely spread and began to replace the ways of legacy roaming calls. However, the saving call products still popular is due to OTT services are inferior to those of mobile communication in terms of voice quality and mobility. Apart from this, both parties of OTT services are subject to the same application software, e.g. LINE cannot communicate with WeChat. Since roaming traffic should be delivered through the routing protocol between local service network and international cooperative operators, it may cause Tromboning and Triangular problems. Operators, should thus increase the cost of interconnection due to the corporation among international operators. To resolve the problems, we propose to use roaming gateways based on the underlying infrastructure without adding components to the existing telecommunication core network. Roaming gateways can assist in separate processing of roaming signals delivery of the current mobile communication networks. The proposed method adopts the current registration model when roaming users visit a service network. Aside from this, the method dynamically updates users’ data in order to reduce the use of computing resources of core network components. The method is proved to be able to choose more direct paths in making roaming calls. The proposed method is verified by both mathematical analysis and simulations. The mathematical analysis proves that the proposed method is able to reduce roaming routing cost in terms of numbers of countries, network components and interconnected operators. The simulations show that the proposed method is able to shorten the answering time of roaming calls and enhance the computation efficiency of the front-end components of mobile communication network. In summary, the proposed method is able to solve the routing problems of Tromboning and Triangular as well as reduce the traffic routing cost of operators. As the result, the operators will be able to offer better tariff to users.