On Crosstalk-Free BPC Permutations Routing in an Optical Variable-Stage Shuffle-Exchange Network

Gennady Veselovsky and Ankur Agrawal


Interconnection Networks, Optical Networks, Crosstalk Avoiding


The paper introduces an approach for crosstalk-free bit-permute-complement (BPC) permutations routing in hybrid optical variable-stage shuffle-exchange networks (SENs) of size N×N where N=2n, and the number of stages m can vary in 1m≤2n-1. The number of stages should be asserted as required by a given BPC permutation for its admissibility. The crosstalk is caused by interacting of two optical signals within the same switch, it can be avoided by decomposing a given permutation to partial permutations which exclude such coupling. In an ideal case the partial permutations should be two semi-permutations with each realizable for one pass through the network. The proposed O(NlogN) algorithm provides an optimal solution for m-stage optical SEN with m in the range, but for n≤2n-1 produced semi-permutations might require further decomposing. It depends on the construction of transition matrix, which can be different for the same BPC permutation. Some guidelines for this case are given.

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