二階異質無線隨意網路架構及其負載平衡繞徑問題

Abstract

無線隨意網路近來受到廣泛的注意，一般而言，我們將其視為一獨立之網路。在此論文中，我們提出二階異質無線隨意網路架構，使其具有連結網際網路之能力。這網路的低階部分包含了一群配備無線網路卡的行動主機；為了連結網際網路以及克服網路分割問題，網路的高階部份由部份具有連接電話網路或基礎網路能力的行動主機所構成，我們稱之為閘道器。而這些高階閘道器的網路介面可以是無線網路、PHS手機或GPRS手機等，各具有不同的頻寬特性。由於閘道器的頻寬較狹小，很容易就成為網路傳輸的瓶頸，我們在此提出了三類的方法來處理負載平衡繞徑之議題，分別是 boundary-moving、host-partitioning 以及 probabilistic 方式。同時，我們考量了一些實作上的問題。模擬的結果以及一個負載平衡繞徑原形之實作都將呈現在此論文中。

The mobile ad hoc network (MANET) has attracted a lot of interest recently. However, most of the existing works have assumed a stand-alone MANET. In this thesis, we propose a two-tier, heterogeneous MANET architecture which can support Internet access. The low tier of the network consists of a set of mobile hosts each equipped with an IEEE 802.11 wireless LAN card. In order to connect to the Internet and handle the network partitioning problem, we propose that the high tier is comprised of a subset of the mobile hosts, called gateways, which can access to cellular / infrastructure networks. The high tier is heterogeneous in the sense that the network interfaces in the gateway hosts could be IEEE 802.11 cards, PHS handsets, or GPRS handsets characterized by different bandwidths and latencies. Observing that the gateways could become the bottlenecks of the two-tier network, we propose a set of solutions, namely boundary-moving, host-partitioning, and probabilistic solutions, to solve the load-balance routing issue. Implementation issues/concerns of these schemes are discussed. Simulation results are presented to compare these load-balance routing schemes. Prototype implementation experiences of such a network architecture is also presented.