Proposed Modification in ETSI GSM 06.10 Full Rate Speech Codec for High Rate Data Hiding and its Overall Performance Analysis

Paper proposes modifications in grid selection strategy in Regular Pulse Excitation module of ETSI GSM 06.10 Full Rate 13 kbps coder which offer overall reduction in 1.8 kbps (36bits/each 20ms frame) bit-rate that in turn can be utilized for high bit rate data hiding. So, the suggested modifications in above coder allow joint data hiding and speech coding. In this spared bit rate of 1.8 kbps, the steganographic data like text, audio and image can be embedded in class Ib (as per GSM Full Rate Channel coding standards) in order to provide error protection and then reliably transmitted. The obtained results for objective and subjective analysis reveal that there is a marginal reduction in perceived speech quality for the case of steganographic FR coder when compared with recovered speech quality in the case of standard GSM FR coder. Apart from hiding data, the proposed modifications in GSM FR is useful for overall reduction in codec bit-rate and provides room for better error concealment at channel coding. As a potential application, the hidden bits may be used for Band width Extension (BWE) purpose.