Modified silence suppression algorithms and their performance tests

In packet voice communication systems, silence suppression algorithms are employed to achieve bandwidth efficiency by suppressing the inactive part of the speech. In this paper, we consider a Nortel fixed-point silence suppression algorithm to investigate means of reducing the computational complexity with a little or no loss in the performance. In view of the compact structure and superior performance of the existing Nortel algorithm, certain modifications are introduced without altering the structure of the original design. Based on these modifications, two algorithms are proposed. Results from objective and subjective quality tests show that the performance of each of the two modified algorithms is comparable to that of the Nortel algorithm. As for the average computational complexity, simulation tests based on TMS320C5402 DSK show that reduction of about 40% and 22% can be achieved for the two modified algorithms.