無線網路之高效率位置管理方法

Abstract

由於無線手機的移動性特徵，其位置管理會造成很大的網路控制負荷 。位置管理的設計考量包含無線手機註冊與呼叫建立。過去的方法針對位 置更新與手機呼叫程序提出了各種網路架構，但是大部分的設計都僅針對 位置更新或手機呼叫程序做最佳化。在本論文中，我們設計了兩種裝置， 分別是分散式臨時位置快速記憶體與分散式原始位置紀錄器，以同時針對 位置更新與手機呼叫來降低資料庫存取延遲及減小網路訊務量。經由使用 臨時位置快速記憶體，我們的方法比過去的方法可增加位置更新與手機呼 叫的效能。對於我們所設計的位置管理協定，我們使用有限狀態圖來詳細 說明及驗證協定的正確性。根據分析模式所得的實驗結果顯示，我們的位 置管理程序比其他的方法有較少的原始位置紀錄器存取率、較低手機註冊 成本及呼叫建立成本。此外，使用臨時位置快速記憶體確實可以有效減少 訊務量與資料庫的存取延遲等額外耗費。 The mobility feature of mobile stations (MSs) imposes a large burden on network traffic control as a result of location management. Design issues of location management include MS registration (updating) and call set-up (paging). Previous approaches introduced several network topologies for updating and paging procedures, butmost of them focus on a single problem: either updating optimization orpaging optimization.In this paper, we design two mechanisms, distributed temporary location cache (TLC) and distributed home location register (HLR), to reduce database access delay and to decrease network signaling traffic in both updating and paging. By using TLCs, our approach can improve the performance of updating andpaging in comparison with previous approaches. We represent our location management protocols in finite state diagrams (FSDs) to specify and verify the protocols formally. Experimental results based on our analytic model show that our location management procedures have lower HLR access rate, lower registration cost, and lowercall set-up cost than other approaches. The employment of TLCs indeed has the advantages of reducing signaling and database access delay significantly.