Alhussein Abouzeid Research:



Systems: Communication Networks; Wireless Ad Hoc and Sensor Networks; Peer-to-Peer Networks.

Applied Theory: Stochastic Processes; Algorithm and Protocol Complexity; Multi-layer Optimization; Information Theory; Queuing Theory.


Project "Decision": Optimal Localized Decision Policies in Ad Hoc and Sensor Networks


In computer networks, each node makes decisions based on its local information (i.e. without global knowledge) under uncertain conditions. For example, a sensor network node may need to decide whether to send its local samples immediately, thus minimizing delay, or wait for more samples to aggregate before sending the data, thus minimizing communication energy consumption. Similarly, an ad hoc network node may need to decide whether to select a particular neighboring node to forward a packet to, or to keep searching for other neighbors with more favorable channel conditions.

These types of decision problems are quite common in wireless networks. In our work, we formally define them as stochastic decision problems, and derive optimal policies that maximize the expected reward. For the sensor network problem, we derive optimal threshold-type policies and analyze conditions for the optimality of these simple-to-implement policies. We also design model-free learning algorithms for situations where the conditions for optimality of threshold-based policies do not hold. For the ad-hoc network problem, the problem can be formulated as an optimal stopping problem in a cross-layer design context. We implement the policies in a protocol stack composed of IEEE 802.11 MAC and geographic routing. The simulation results show significant improvements compared to state-of-the-art cross-layer forwarding protocols.



MASS 2006 (includes voice annotation)



Key Publications:

Z. Ye, A.A. Abouzeid and J. Ai, "Optimal Policies for Distributed Data Aggregation in Wireless Sensor Networks," to appear, Proceedings of 26th Annual IEEE Conference on Computer Communications (INFOCOM 2007), Anchorage, Alaska, USA, May 6-12, 2007.

J. Ai, Z. Ye and A.A. Abouzeid, Cross-layer Optimal Decision Policies for Spatial Diversity Forwarding in Wireless Ad Hoc Networks, Proceedings of Third IEEE International Conference on Mobile Ad-hoc and Sensor Systems (MASS 2006), October 9-12, 2006, Vancouver, Canada.