Fault Tolerance in FFT Arrays: Time redundancy Approaches

Time redundancy is suggested as a viable solution for the two-dimensional fast Fourier transform (FFT) array directly corresponding to the FFT flow graph. Two approaches are presented, one based on interstage reconfiguration and the other on intrastage reconfiguration, both allowing for survival to multiple faults with limited increase of network complexity and very small hard-core sections. With both approaches, the processing speed in the presence of faults is halved with respect to the nominal speed. Reliability and survival ratios to multiple faults are evaluated for the two cases, taking into account the area increments necessary for fault tolerance.