行動電話細胞話務之模擬與分析

Abstract

細胞式陸地行動電話系統中『細胞』（Cell）是通信頻道的管理單位，也 是信號涵蓋區的探討對象．細胞的信號涵蓋區通常是一種不規則的形狀， 而且是相互重疊的（Overlapped）；而行動電話系統所特有的呼叫特性如 ：直接再試（Direct Retry）及頻道交遞（Hand-Off）等也都關係到許多 細胞．在這種情況下，若想以傳統的分析方法預估系統的運作品質，並無 法顯示出『行動』電話的動態特性．因此，利用電腦的快速運算功能模擬 行動電話細胞話務的處理過程，以預估各項話務品質參數，不失為一個可 行的辦法．本篇論文提出一套可反映出實際行動電話細胞話務及服務區現 況的模擬系統，並展示本模擬系統在細胞規劃及維護與品管上的應用．在 設計本系統時，我們依據實際的話務處理流程建立『行動電話細胞話務模 型』；採用地圖切割的數位化方塊來表示系統服務區的現況．由於話務處 理基本上屬個別事件（Discrete-Event），本論文利用ｓｍｐｌ做為模擬 程式的輔助工具． This thesis proposes a cellular mobile traffic simulation sys- tem which can reflect the real coverage and signal environment. In the Cellular Mobile System, The CELL coverage areas are normally irregular and overlapped. The call processing features, i.e. Direct-Retry and Hand-Off, involve many cells. Under this circumstance, It is difficult to analyze or estimate the Quality- of-Service (QOS) through traditional analytical calculations. Computer simulation offers a feasible way to estimate these QOS parameters. We have built a Model which adopted the geographical information in coverage and signal representation, followed by the real system call processing scenarios which can make the results more realistic. Via simulation, the maintenance, design and traffic management personnel are able to make right decisions . Since call processing procedures are discrete-events, we use ｓｍｐｌ as a tool to implement simulation model.