This work deals with low bit-rate speech coding using joint segmentation and vector quantization. Low bit-rate quantization of LSF parameters can be achieved by combining segmentation and quantization, where a segment consists of one or several adjacent LSF vectors. It models the input LSF vectors as a sequence of variable length segments with the option to skip over segments which are then interpolated at the decoder. The codebook design algorithm assumes an ideal channel. That is, the received index is identical to the transmitted one.
Practical channels introduce errors in the transmitted data.
One can reduce the effect of channel errors by using codebook design algorithms that combine knowledge on the channel. Index assignment is one such method. In the modified BSA we use a weighted cumulative distance measure of all available segments lengths between two codewords. We propose a distance metric which uses fixed weights LSF codewords. The modified BSA was used to improve random and NBO index assignments.