Resource Allocation Issues in
Communication Networks
Tara
Javidi
PhD Candidate
University of Michigan
Department of Electrical
Engineering and Computer Science
Rapid growth in size of communication networks and the
complexity of applications and offered services provide numerous challenges in
the design and study of communication systems. Resource allocation is a major
component of network utilization and quality of service provisioning in such
systems. Because of scarcity of resources and the demand for better quality of
service, optimal resource allocation problems play an ever-increasing role in
the design and analysis of communication networks. In this talk the merits and
elements of an analytic approach to such problems are discussed, first. Then, a
few examples of resource allocation issues in networking, from connection
admission control in cellular systems to scheduling algorithms in high speed
routers to routing in ad hoc wireless networks, are introduced briefly. Finally
the following connection admission problem in wireless networks is presented.
The mobile wireless environment, in particular, provides
serious challenges such as limited bandwidth, low capacity channels, and
interference among users. As a result, an important network layer problem in
the design of cellular systems is how to allocate the limited resources (e.g.\
bandwidth) efficiently, while providing quality of service (QoS) guarantees to
the applications in terms of bit-rate and loss. This problem becomes more acute
for the next-generation integrated-services networks which aim to support
heterogenous traffic which aim to support heterogenous traffic. In cellular
networks desirable resource allocation is mainly achieved by the base station
through connection admission decisionsin the presence of new connection
requests. Granting an admission is equivalent to a contract where the newly
connected service is guaranteed a set of desirable QoS measures for the full
length of the connection, while generating revenue at a prespecified rate. As a
result, an efficient allocation of resources is achieved by constructing a
connection admission strategy that maximizes the average expected revenue and
satisfies the QoS requirements of each connected service. In this talk it is
shown that, mathematically, this problem can be represented as a constrained
stochastic dynamic optimization problem where the QoS requirements form a
dynamic set of constraints. In general such an optimization problem is
computationally and analytically intractable. As an alternative approach, we
propose a decomposition (possibly suboptimal) of the problem into two tractable
subproblems. Furthermore, it will be shown that such a decomposition creates a
conceptual framework for understanding the interaction among various layers of
the system such as physical layer concerns, QoS requirements, and network layer
resource allocation. The nature of these sub-problems in a cellular system with
an outage-based QoS requirement is illustrated and the results are discussed in
detail.
3:30 - 5:00 p.m.
1500 EECS