Vergetis, Evangelos

Email Address
ORCID
Disciplines
Research Projects
Organizational Units
Position
Introduction
Research Interests

Filters

2003 - 20052
2
11
Reset filters

Settings

Search Results

Now showing 1 - 2 of 2
  • Publication
    Forming Connected Topologies in Bluetooth Ad-hoc Networks – An Algorithmic Perspective
    (2003-08-01) Guérin, Roch A; Rank, Jacob; Sarkar, Saswati; Vergetis, Evangelos
    This paper represents a first step in exploring the formation of connected topologies in ad-hoc networks built on the Bluetooth technology. Connectivity is the most basic requirement for any system aimed at allowing devices to communicate with each other and in this paper we illustrate that this seemingly innocuous goal gives rise to many significant challenges in the context of the Bluetooth technology. We start with a brief overview of Bluetooth and its operation and then identify some of the major problems the technology faces when used to build ad-hoc networks. The paper's contributions are in introducing basic algorithmic problems associated with building connected Bluetooth networks and in developing several possible solutions capable of generating "good" connected topologies.
  • Publication
    Realizing the Benefits of User-Level Channel Diversity
    (2005-10-01) Vergetis, Evangelos; Guérin, Roch A; Sarkar, Saswati
    Channel or path diversity is known to improve performance in physical layer designs, channel access strategies, path switching mechanisms, etc. In this paper, we focus on "user-level" mechanisms that operate simply by distributing packet transmissions across multiple channels. We seek to understand when, why, and to what extent this can be of benefit, and equally important, whether these benefits can be realized with as little of an added cost as possible. In that context, our main contribution is not so much in identifying optimal policies for leveraging channel diversity, but in introducing the concept of channel "equivalence" and demonstrating that channel diversity yields substantial benefits mostly when channels are approximately equivalent. We build on this finding to investigate the robustness of these improvements against errors in the characterization of the available channels or changes in their characteristics. We also explore the sensitivity of the results as the number of available channels varies. The findings of the paper demonstrate that by allowing packet transmissions from multiple users to intelligently share channels, it is possible to improve overall performance and robustness through simple and portable user-level mechanisms.