An overlap save algorithm for block convolution with reduced complexity

We propose a block convolution algorithm that requires shorter length FFT than the conventional overlap save algorithm (OSA). It is shown that the OSA can be split into two separate processes related to the previous and current data blocks. Hence, only current data block needs to be transformed in the proposed OSA, whereas the concatenated block of previous and current data is transformed in the conventional method. As a result, the number of arithmetic operations for the block convolution is reduced. Also, the reduced transform size gives additional advantage in data manipulation when implemented on DSP and PC.