網路電話與公眾電話/行動電話之智慧型服務

Abstract

在越來越競爭的電信市場上，如何提供創新的服務以滿足客戶的需求越形重要。論文中針對智慧型服務相關的整合型預付式扣款服務、安全的行動電子付款模式、回呼叫機制與電信客戶服務帳務系統做了廣泛且深入之研究。 首先整合型預付式扣款服務探討在一個預付式帳戶下如何同時提供行動通信語音與數據服務，我們研究CAMEL協定提出通信及扣款程序；而如何降低扣款過程中二種服務同時被中斷的機率是複雜的問題，我們提出一演算法，建立其分析模式並完成數據的模擬以驗證結果。 當越來越多行動加值服務的推出以吸引客戶使用時，就需要一個安全的電子付款交易模式，我們探討提出基本需求及建立這個模式的架構，並因應行動終端設備性能的限制研究以低複雜度的ID-based驗證技術來滿足交易的安全性。 在私有電信網路的配號限制下，對外通信常造成被叫者一些識別不便，我們提出回呼叫表格處理機制來克服問題，並研究通信行為提出避免回呼叫碰撞之演算法，及建立分析模式。 最後於附錄中加入電信客戶服務帳務系統，這是電信業者必備之營業支援系統，藉此管理客戶資訊以提供客戶滿意的服務。

In today’s highly competitive telecommunications environment, the emphasis has shifted to delivering innovative service while to satisfy increasingly sophisticated customers’ need. This dissertation first introduces an Integrated Mobile Prepaid Services. Prepaid personal communication service (PCS) users have outnumbered postpaid users. We study the charging issues of an integrated GSM and GPRS prepaid service, where a single prepaid account provides a user both voice and data services. The call setup and charging procedures for GSM and GPRS are presented using the CAMEL network architecture. To reduce the probability of terminating both on-going voice and data calls, we suggest that no new call be admitted when the user credit is below a threshold. An analytic model has been developed to evaluate the performance of the approach. Computer simulations have also been used to verify the results. The numeric results indicate that the forced termination probability can be significantly reduced by choosing an appropriate threshold of the user credit. When the basic functionalities of a wireless mobile network have been achieved, customers are then more interested in value-added mobile applications. In order to attract more customers to such mobile applications, a solid, secure and robust trading model is a must. We propose such a secure trading model named Mobile Electronic Payment (MEP) for wireless mobile networks, which applies the emerging ID-based cryptography for key agreement and authentication. Our MEP attempts to alleviate the computational cost, reduce the memory space requirement in mobile devices, and meet the requirements for secure trading: avoidance of overspending and double spending, fairness, user anonymity and privacy. Our design is transparent to the bearer networks and is of low deployment cost. We expect that our MEP provides a viable trading architecture model for the future mobile applications. Private Telecommunications Networks (PTNs), such as enterprise telephony and Voice over IP (VoIP), have been widely deployed in the recent years. A common limitation of PTNs is that the PTN users are usually not assigned with E.164 numbers that are routable in Public Switched Telephone Network (PSTN). When a PTN user initiates a call to a PSTN user, it is not possible to use the PTN calling party’s identifier as the caller ID; instead, an E.164 number of the PBX or VoIP gateway is used. Therefore, the PSTN called party cannot use the caller ID to call back to the PTN calling party directly. We propose a callback table approach to resolve this issue. We describe how the PTN call-out information is stored into and retrieved from the callback table in the PBXs or VoIP gateways to provide callback service. Numeric analysis has been performed to evaluate the feasibility of this approach. The numeric results indicate that the callback method performs better as there is more voice traffic served by a VoIP gateway. These research results presented in this dissertation can be viewed as a useful foundation for further study in intelligent services for VoIP and PSTN/PLMN networks. In appendix we introduce customer care and billing system for telecommunication, which is of the Business Support System (BSS). We present how customer service and billing system are managed in the mobile market.