A Lookahead Speech Encoding Technique

It is well known that, in a speech communication, variable delivery delays of speech packets pose as much problems as the absolute overall delivery delays. A new speech encoding technique specifically designed to cope with possible losses as well as variable delays is studied assuming a packetized speech transport network. The encoding scheme combined digital representations of speech waveform over two consecutive packet generation intervals. Over a packet generation interval a full representation is transmitted along with a coarse representation of the next packet generation interval. The receiver thus is always equipped with the coarse representation of the next reconstitution period. When a packet is lost on the way or delayed over the reconstitution period, the receiver can utilize the lookahead section of the previous packet to approximate the speech over the next reconstitution period. Experiments with the lookahead encoding is not complete and the outline of the planned experiments will be provided.