Missing Packet Recovery Techniques for DM Coded Speech

• Main Authors: Jou, Shiang-Peng, 周相鵬
• Other Authors: Wen-Whei Chang
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/91436402108659895257

碩士 === 國立交通大學 === 電信研究所 === 85 === Packet communication increases the utilization efficiency of channel capacity by exploiting the bursty nature of voice traffic. Depending upon the contents of speech packets, numerous recovery techniques have been proposed to combat the packet loss due to channel impairments or excessive delay. Most previous research has emphasized the pissing packet recovery techniques for PCM and DPCM coded speech. When using a DM encoder, however, the missing samples in the discarded packets cannot be reconstructed by zero-amplitude stuffing or waveform substitution techniques. In this thesis, we show that the packet loss effects of DM system or using a tree search interpolation. In this work, we first provide experimental results for EDM coding of speech sources under packet loss conditions. For the tree search interpolation, we explore the benefits of delayed decoding by using an interpolative DM code generator to form a tree of sample possibilities given the remaining adjacent samples.