A TIME-DOMAIN APPROACH FOR AVOIDING CROSSTALK IN OPTICAL BLOCKING MULTISTAGE INTERCONNECTION NETWORKS

Crosstalk in Multistage Interconnection Networks can be avoided by ens uring that a switch is not used by two connections simultaneously. In order to support crosstalk-free communications among N inputs and N ou tputs, a space domain approach dilates an N x N network into one that is essentially equivalent to a 2N x 2N network. Path conflicts, howeve r may still exist in dilated networks.This paper proposes a time domai n approach for avoiding crosstalk. Such an approach can be regarded as ''dilating'' a network in time, instead of space. More specifically, the connections that need to use the same switch are established durin g different time slots. This way, path conflicts are automatically avo ided. The time domain dilation is useful for overcoming the limits on the network size while utilizing the high bandwidth of optical interco nnects. We study the set of permutations whose crosstalk-free connecti ons can be established in just two time slots using the time domain ap proach. While the space domain approach trades hardware complexity for crosstalk-free communications, the time domain approach trades time c omplexity. We compare the proposed time domain to the space domain app roach by analyzing the tradeoffs involved in these two approaches.