2) Mon, 3/27/06, 5:10 pm, NEB 409

Woong Cho: 
"Optimum Resource Allocation for Relay Networks with Differential Modulation"

Abstract:
In wireless networks, relay transmissions can enable cooperative
diversity by forming virtual antenna arrays. The optimum resource
allocation in such relay networks is critical to enhance their
performance and efficiency. However, existing works on resource
optimization only consider single-relay systems and focus on the power
allocation. In this paper, we consider both the power optimization and
the location optimization for systems with arbitrary number of relays.
Equally attractive is that our investigation is tailored for
differential modulations, which bypass the channel estimation
at the receiver and are particularly suitable for wireless relay
networks. We first derive an upper bound of the error performance. Based
on this bound, we then develop the optimum energy and distance
allocation schemes that minimize the average system error. Analytical
and simulated comparisons confirm that the optimized systems provide
considerable improvement over un-optimized ones, and that the minimum
error can be achieved via the joint energy-location optimization. In
addition, we show that location optimization may be more critical than
energy optimization.