Turbo-detected unequal protection audio and speech transceivers using serially concantenated convolutional codes, trellis coded modulation and space-time trellis coding

Abstract

The MPEG-4 TwinVQ audio codec and the AMRWB speech codec are investigated in the context of a jointly optimised turbo transceiver capable of providing unequal error protection. The transceiver advocated consists of serially concatenated Space-Time Trellis Coding (STTC), Trellis Coded Modulation (TCM) and two different-rate Non-Systematic Convolutional codes (NSCs) used for unequal error protection. A benchmarker scheme combining STTC and a single-class protection NSC is used for comparison with the proposed scheme. The audio and speech performance of both schemes is evaluated, when communicating over uncorrelated Rayleigh fading channels. An Eb/N0 value of about 2.5 (3.5) dB is required for near-unimpaired audio (speech) transmission, which is about 3.07 (4.2) dB from the capacity of the system. © 2005 IEEE.