Abstract: Interconnection length is an important layout property of electronic designs. A reliable interconnection length estimation is essential for improving placement and routing techniques. By considerring external interconnection, an improved prior wire length estimation method is proposed. Interconnection length distribution and average interconnection length expression for external interconnection are obtained by taking into account the inherent features of the optimal placement process. By considerring both internal and external interconnections at the same time, an analytical form for the average wire length is obtained. Experimental results for several benchmark circuits show that the new method is more accurate than the Donath and Improved Donath technique by 29% and 5% respectively.

Key words: external interconnection, optimal placement, wire length estimation