Abstract
In this paper, we propose a combined variable-rate code-excited linearly predictive (QCELP) speech coding and unequal error protection (UEP) channel coding system for wireless communications. In contrast to the conventional schemes, our system employs a concatenated super-imposed rate-compatible punctured convolutional (SI-RCPC) channel coding scheme which can provide UEP with respect to not only the bit-significance of speech packets but also the speech activity and local channel characteristics. Verified by the simulation results, the combined system achieves an average transmission rate less than 8 kb/s as well as an average 2 dB signal-to-noise ratio (SNR) gain over the conventional equal error protection system.