Seamless Communications

Abstract

The evolution of today’s wireless technologies and small hand-held devices has enabled the handling of the trade-off between mobility and performance. Things have, however, become more complex. Users demand high performance when using small and resource-efficient devices. Users also demand high-performance connectivity anywhere and anytime without having to care about transitions between different access networks. As of today, the absence of Mobile IP (MIP) support in most networks implies the need for a reconnection of the service as soon as the access network changes. That is why a new seamless communication concept is required. In the thesis, a new seamless communication concept is proposed. The goal is to be Always Best Connected (ABC) even if the conditions change. Initially, a network link has to be selected and a connection has to be established. The service used should be maintained as long as the conditions are fulfilled. First, a set of Generic Services (GSs), each related to a specific communication task, is defined. Furthermore, a deep performance investigation of some of the wireless technologies available is summarized and used. Based on the combination of a GS and a wireless technology selected criteria are used. The data extracted from our measurements have the option of later being fed into statistical algorithms. The translation of the extracted information through the statistical methods could be non-linear and for that reason the Fuzzy Set Theory (FST) is used. The FST provides us with the tool needed for the next step, the decision aiming at ABC. To be able to handle the large amount of data, the Multi-Criteria Decision Making (MCDM) is used. This decision model requires a linguistic 9-point scale which suits the FST tool perfectly. A judgment between different criteria can then be made. Moreover, the thesis describes a couple of important issues regarding the Internet protocol address problem. Each problem is discussed and solutions are presented in the context of having seamless communication without today’s constraints. The result is a seamless communication concept that is more flexible than other solutions. Both the FST and the MCDM tools have been successfully implemented into a running prototype