減少智慧型網路及個人通信服務網路訊號量之研究

Abstract

由於目前智慧型網路及個人通信服務網路皆使用集中式資料庫來提供服 務, 而集中式資料庫會產生訊號量集中的缺點, 進而導致網路不穩定, 故 需考量訊號量之分散. 本論文提出兩種方法來解決, 一是分散式資料庫的 方法, 一是研究訊息格式並嘗試將數筆訊息組合為一. 採用分散式資料庫 是利用電信用戶有區域性的通話行為, 因此以一特定編碼之資料庫來服務 較大區域之用戶群, 藉以分散網路負荷, 達到降低訊號量之目的. 對於網 路上訊息的格式, 我們亦發現當訊息之目的相同時, 將會有相當大的資訊 相同, 因此可將同一目的點的訊息在信號轉送點組合, 到目的點再拆開, 藉由少傳送這些相同資訊來降低訊號量. 此外, 當個人通信服務網路要提 供寬頻多媒體服務時, 無線非同步傳輸模式網路是一個適當的架構, 而要 使用戶在此高速網路的環境下移動, 我們必須將傳輸協定簡化. 因此, 本 論文提出一種細胞編號方式, 讓用戶在移動時, 重新路由可以最快速, 最 節省網路資源方式進行. The Intelligent Networks (IN) and Personal Communication Service (PCS) networks use centralized databases to provide services to users. A serious problem with centralized database services is the heavy concentration of signaling traffic on the links leading to the databases. In this dissertation, we propose two approaches to reduce the traffic. The first approach proposes the signaling network deployment for mobile networks with a goal of reducing the signaling cost and time to set up calls. The deployment exploits the features of the distributed databases, data partition, locality of mobile users, and Signaling System No. 7 (SS7) network architectures. The proposed method can reduce over 95% of the location-updating cost and 70% of the location-tracking cost under a general simulation model. The second approach focuses on the formats of the messages exchanged among signaling points. We propose a simple assembly/disassembly part (ADP) for the SS7 protocol to reduce the signaling traffic loads in both the PCS and IN netwoksThe ADP combines two or more messages with the same destinations into a singlemessage thereby reducing signaling traffic without affecting SS7 protocoloperations. The numerical results show the proposed method can reduce traffic among signaling points 9% ~ 17%. The future PCS network must provide multimedia services to users. A potential network is by using the Asynchronous Transfer Mode (ATM) as its backbone. In this dissertation, we also propose a Cell Numbering Plan for mobile stations to hanndoff seamlessly to the cells of a wireless network with ATM switches as its backbone. We propose an Automatic Rerouting Strategy (ARS) to support the rerouting of ATM cells during the handoff. The Cell Numbering Plan assigns each group of cells a number from 1 to 5, which ensures that neighboring cell groups will have different numbers. Any mobile station that takes a handoff between any two neighboring cell groups can automatically reroute its ATM cells using a simple calculation. Furthermore, by using the ARS strategy, the path between the originating and terminating mobile stations will be the shortest whenever either of them moves. The signaling bandwidth that is used for handoff in this strategy is believed to be the least among the methodologies reported to date.