Performance of coded speech modulated signals through Rician-fading mobile channel

A modified approach for estimating the bit-error-rate (BER) of a q-branch coherent reception for an antipodal binary-modulated transmitted speech signals through an independent Rician fading channel is described. Analysis-by-synthesis (AbS) speech coders are the candidate coders for producing good quality speech in the range from 4.8 to 16 kb/s. The issues of transmitting 8 kb/s analysis-by-synthesis speech coders over a Rician-fading mobile radio channel are discussed. The statistics of the received signal envelope on each branch follow a Rician distribution and independent. The performance results will demonstrate the severe penalty in signal-to-noise ratio (SNR) that must be paid as a consequence of the fading characteristics of the received signal. We shall then show that the penalty in SNR can be reduced by means of diversity. The BER results are obtained without using channel coding or error-correcting codes. The amount of the minimum value of channel SNR that required for obtaining a good speech quality or a specific target BER is proposed.