This thesis devises quantization and source-channel coding schemes to increase the error robustness of the newly standardized ITU-T G.711.1 speech coder. The schemes employ Gaussian mixture model (GMM) based multiple description quantizers (MDQ). The thesis reviews the literature focusing on GMM based quantization, MDQ, and GMM-MDQ design methods and bit allocation schemes. GMM-MDQ are then designed for the quantization and coding of the MDCT coefficients in the G.711.1 speech coder. The designs are optimized for and tested over packet erasure channels. Performance of the designs are compared with Mohr's forward error correcting code based multiple description coding (MDC) scheme. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-06-02 16:02:11.727