Algorithmic Aspects of Communication Networks
Dr. T. Erlebach
The importance of communication networks is ever-increasing.
After the advent of mobile and easy-to-use devices for computing
and communication, people expect to be able to communicate
efficiently with friends, collaborators, or service providers
at any time,
no matter whether they are in an office, at home, or
travelling. New applications such as video-on-demand, telemedicine,
or distance learning place high demands on the quality and
bandwidth of transmissions.
In order to provide a ubiquitous and powerful communication
infrastructure that can satisfy these demands, sophisticated
network technology, protocols and algorithms are required.
We are interested in the design and analysis of algorithms that
are useful in the design, evolution, and operation of complex
communication networks. Examples of problem areas that we
In all-optical networks, data is transmitted from the sender to
the receiver in optical form. Wavelength-division multiplexing
is used to partition the huge capacity of optical fibre into
channels. The challenges arising in the design and operation
of such networks include routing and wavelength assignment,
throughput maximisation, and placement of wavelength converters.
Algorithms for Internet Analysis
The Internet is a large and complex network that is the
result of distributed growth without central control.
It is a challenge to understand and analyse the structure and
behavior of the Internet. We are interested in designing
algorithms that can be used to assess the robustness and
reliability of the Internet or that can improve its
efficiency or security.
Call Admission Control
For applications such as video conferences or distance learning,
it is desirable to reserve bandwidth for each established
connection in order to provide a guaranteed quality of service.
But often the capacity of the network is not sufficient to
accomodate all connection requests made at any time. Thus, it
is important to find a good strategy for deciding which requests
to accept and which to reject. The goal is to accept as many
requests as possibe without exceeding the capacity of the network.
We are interested in on-line and off-line approximation algorithms
for this optimisation problem for various network topologies.
With the increasing mobility of users and the availability of
low-cost wireless communication devices (e.g. mobile phones),
wireless networking is becoming an increasingly important
research topic. The characteristics of transmissions in
wireless networks differ substantially from conventional
wired networks, and thus innovative approaches and techniques
are required. We are interested in problems such as
resource allocation, scheduling and load balancing arising
in cellular networks or mobile ad-hoc networks.