Research of an Efficient Simulated Annealing Algorithm in the Very Low Bit Rate Speech Coding
Xiongwei Zhang, Pla Uni · Acta Simulata Systematica Sinica · 2004
An improved simulated annealing algorithm is proposed and applied to the 600bps speech coding to solve the problem of low quantization SNR and the poor performance in noisy channels. First, the algorithm is used to design the codebook of the speech coding parameters. And then, simulated annealing algorithm is employed to assign binary codewords to the codebook to improve the speech quality in noisy channels. Simulation results show that the quantization SNR of the algorithm is about 0.4dB better than that of the traditional LBG algorithm, and the improvement of average distortion per bit error exceeds 60% compared to randomly selected codewords. The result of informally subjective listening test indicates that the intelligibility and naturalness of the 600bps vocoder is quite well. Furthermore, the speech coding algorithm is robust in a noisy channel with 1% BER.