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VLSI Design
Volume 2009 (2009), Article ID 537341, 13 pages
Research Article

A Multilevel Congestion-Based Global Router

1Department of Electrical and Computer Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada T2N 1N4
2School of Engineering, University of Guelph, Guelph, ON, Canada N1G 2W1
3Department of Industrial and Systems Engineering, P. C. Rossin College of Engineering and Applied Science, Lehigh University, Bethlehem, PA 18015, USA

Received 17 February 2009; Revised 13 July 2009; Accepted 2 September 2009

Academic Editor: David S. Kung

Copyright © 2009 Logan Rakai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Routing in nanometer nodes creates an elevated level of importance for low-congestion routing. At the same time, advances in mathematical programming have increased the power to solve complex problems, such as the routing problem. Hence, new routing methods need to be developed that can combine advanced mathematical programming and modeling techniques to provide low-congestion solutions. In this paper, a hierarchical mathematical programming-based global routing technique that considers congestion is proposed. The main contributions presented in this paper include (i) implementation of congestion estimation based on actual routing solutions versus purely probabilistic techniques, (ii) development of a congestion-based hierarchy for solving the global routing problem, and (iii) generation of a robust framework for solving the routing problem using mathematical programming techniques. Experimental results illustrate that the proposed global router is capable of reducing congestion and overflow by as much as 36% compared to the state-of-the-art mathematical programming models.