WiMAX環境下以停留時間為基礎的ASN-GW重新定錨演算法

Abstract

在WiMAX點對點網路架構（WiMAX End-to-End Network Architecture）中，為了降低換手（Handover）延遲，當行動裝置（Mobile Station）在存取服務網路（Access Service Network）以及基地台（Base Station）之間移動時，會使用存取服務網路換手（ASN anchored mobility）。然而在行動裝置都不更換定錨點的狀況下，存取服務網路換手會導致存取服務網路閘道器（ASN Gateway）的負載大幅增加。因此，行動裝置需要一個機制來決定何時執行重新定錨（Relocation），以及決定需要重新定錨的行動裝置的數量及對象。在本篇論文中，我們提出了一個以平均停留時間為基礎的存取服務網路重新定錨演算法，在適當的時機針對適合的行動裝置進行重新定錨。模擬的結果顯示出，我們提出的演算法可以有效的降低與穩定存取服務網路閘道器的負載情形，並且降低了整個系統在進行重新定錨的負擔。

In the WiMAX End-to-End Network Architecture, the mobile station (MS) performs Access Service Network (ASN) anchored mobility to lower handoff latency when it moves between base stations (BSs) and ASNs. However, the ASN anchored mobility will induce a heavy load of ASN gateway (ASN-GW). Thus, relocating anchored ASN-GW for the MS is needed. It is a challenge for system designers to decide when to perform ASN-GW relocation, how many MSs should be relocated and which MSs should perform relocation. In the thesis, we propose an average residence time based (ART-based) ASN-GW relocation algorithm to determine an appropriate time and select a set of MSs to relocate their anchored ASN-GWs. The simulation results show that the ART-based ASN-GW relocation algorithm can reduce and steady the loads of ASN-GWs and decrease the cost for performing relocations.