標題: 提升固定式與行動通訊整合環境之號碼可攜服務效能
Enhancing The Efficiency of Number Portability Service on Fixed-Mobile Convergence Environment
作者: 鄭靜紋
Ching-Wen Cheng
鍾乾癸
Chyan Goei Chung
資訊科學與工程研究所
關鍵字: 電信網路;號碼可攜;效能;快取;Fixed-mobile convergence;number portability;efficiency;cache
公開日期: 2006
摘要: 在通訊環境整合之前, 固接式電話(fixed-lined)與行動電話(mobile)通常各別維運,通訊服務也各自獨立。固定式與行動通訊整合環境(Fixed-mobile convergence, FMC)提供一個可供固接式與行動電話業者互通並分享服務的共同平台, 將兩種電信網路的通訊服務、通訊網路、以及營運與商業模式結合為一個整體。在此平台上,固接式與行動電話的使用者能無阻礙地彼此通訊。 隨著通訊技術精進,電信自由化,以及通訊市場成熟,更多業者投入FMC的電信通訊市場。使用者有更多機會根據業者提供的服務項目、服務品質、以及收費機制選擇最適合的電信公司,更換電信服務公司的意願與機會也隨之提高。在此競爭激烈的電信環境中,能讓使用者即使更換電信服務公司,也依然能保有原來電話號碼的號碼可攜服務(number portability service)成為重要的服務項目。電信公司必須提供號碼可攜服務以吸引更多使用者,藉此提昇本身的市場競爭力。 號碼可攜服務實行之前,每個固接式或行動電話號碼可對應到使用者所屬電信服務公司的特定交換機,經由該交換機即可連結到該號碼對應的實際位址。然而,號碼可攜服務打散了電話號碼與電信公司以及使用者實際位址之間的關連性。為了將可攜式號碼重新對應至使用者的實際位址,電信公司必須建立一個共有的可攜式號碼資料庫(number portability database, NPDB)以管理FMC環境中所有可攜式號碼與使用者實際所在位址間的對應關係,並委由一個中立的可攜式號碼管理機構(number portability administration center, NPAC)管理。電信公司經由查詢NPAC而將可攜式號碼轉換為使用者的實際位址,進而接通撥打給可攜式號碼的電話。 NPDB的規模會隨著號碼可攜服務的使用者增加而擴大,當使用者數量很大時,NPDB隨之增大,可能造成資料搜尋時間增加,使得整體可攜式號碼轉換的時間延長。然而,NPAC的處理速度以及傳輸流量皆有限,為了進行可攜式號碼轉換所引發的大量NPAC查詢可能造成NPAC與網路壅塞,並阻礙其他話務進行。此外,自使用者撥出電話號碼開始,直到電話被接通,需佔用通訊頻寬進行接通話務的訊號傳輸。當撥打給可攜式號碼的電話數量增加,而可攜式號碼轉換的時間又延長,會降低通訊網路的使用效能與服務品質。 電信網路的架構設計使可攜式號碼的處理、以及號碼轉換時所需要的知識都集中在交換網路(switching network),要提高號碼可攜服務效能,必須降低交換網路壅塞的可能性;因此,必須減少NPAC查詢的數量才能提升號碼可攜服務的效能。根據這項觀察結果,我們提出將可攜式號碼轉換所需的知識分散到其他電信網路元件,由其他電信網路元件負責可攜式號碼轉換,藉此減輕NPAC的運算負擔以及所需處理的話務量。 根據這個想法,我們經由分析使用者的移動與通話行為,提出三項新的機制,以提升FMC環境中號碼可攜服務的效能: 1. 對於傳統固接式電話網路,我們提出將可攜式號碼轉換的知識與功能建立在PBX上。若大部分的可攜式號碼皆在PBX就被轉換為受話端的實際位址,NPAC的查詢量將得到紓解,可攜式號碼查詢與轉換的時間縮短,可使號碼可攜服務效能提升。 2. 對於並未提供數據通訊頻道的2G行動通訊系統,我們提出的作法是以學校、辦公大樓、工廠等機構的區域網路為基礎,建立行動通訊的PBX系統,並將可攜式號碼轉換的知識與功能建立在這類行動通訊PBX上,以達到提升號碼可攜服務效能的目的。 3. 對於具有數據通訊特性的3G行動通訊系統,我們提出的機制為:將個人化的可攜式號碼轉換知識存放於使用者端的智慧型手機,並利用IP網路更新手機上的知識,在使用者終端進行可攜式號碼轉換。此方法可將NPAC的查詢量減到最小,能最有效地紓解經由查詢NPAC以獲取受話端實際位址所造成的號碼轉換延遲。 在此論文中,我們證明經由上述的三項機制,可正確地將可攜式號碼轉換為受話端的實際位址,並可有效減少對NPAC進行可攜式號碼轉換的查詢量,降低可攜式號碼轉換所造成的延遲,提高號碼可攜服務的效能,並且可增進電信網路的使用效能與服務品質。所提出的方法對使用者以及電信服務提供者都有實際上的效益。
Fixed and mobile convergence (FMC) is the combination of previously separate fixed and mobile services, networks, and commercial practices. A common platform to access both fixed and mobile telecommunications services is provided in FMC environment, such that users can set up calls to both fixed and mobile telecommunication systems. Deregulation, market demand, and technological development encourage more service providers to join FMC telecommunications market. Users have more choices and are more likely to change service providers according to the service, quality, and the billing policy offered by the operators. Number portability (NP) service allows a user to keep the same telephone number when changing operators. In the competitive telecommunications market, operators must provide NP service to attract subscribers and to enhance their competitiveness. However, NP service broke the relation between telephone numbers and the destination networks. For allowing switching systems to translate a ported number to the destination address, telecommunication operators establish a neutrally operated number portability administration center (NPAC) with a global NP database (NPDB) together to maintain the mapping of ported numbers and the information to reach the destination. NPDB maintains the mapping information of all ported numbers of the FMC environment. The size of NPDB grows enormously along the increase of NP users. The increase of NP users results in a huge NPDB will prolong the latency of data searching. The process and traffic capacity of NPAC is limited that the enormous NPAC queries for ported number translations may block other queries and cause congestion of the switching network. In addition, the communication resource is occupied in call setup process. A large amount of NPAC queries will degrade the utility and service quality of the communication network. Studying the architecture of telecommunications networks, the process and the knowledge of ported number translation is centralized in the switching networks. The efficiency of NP service can be enhanced by minimizing message passing for ported number translation. Hence, our approach is to dispatch the process and the knowledge of ported number translation to other network entities to alleviate the workload and the offered traffic of NPAC. Based on the concept, we investigate the mobility and calling behavior of users and propose three new mechanisms for providing efficient NP service in FMC environment: 1. For fixed-line telecommunication systems, we propose to provide ported number translation functions in PBX-based telecommunications networks. When most NP calls can be translated in local telecommunications network, NPDB queries will be reduced and the efficiency of NP call setup will be enhanced. 2. For 2G mobile telecommunications system which does not provide data transmission channel, we propose an organization-based mobile telecommunications network to act as a mobile PBX to perform ported number translations in mobile local networks. 3. For 3G mobile telecommunications system which provides data communication features, we propose a mechanism to update routing information from NPAC to intelligent user terminals (e.g., 3G/WLAN dual-mode mobile handsets) via IP (Internet protocol) network. Thus, the routing information of ported numbers can be solved in user-end. In this dissertation we prove that the amount of NP queries can be remarkably reduced by the above proposed mechanisms; hence, the efficiency and performance of NP service can be improved without affect the profit of telecommunications operators and users.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT008617815
http://hdl.handle.net/11536/81346
Appears in Collections:Thesis


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