Proposed Modification in ETSI GSM 06.10 Full Rate Speech Codec for High Rate Data Hiding and its Objective Evaluation of Performance Using Simulink

摘要

Today, the primary constrain in wireless communication system is limited bandwidth and power. Wireless systems involved in transmission of speech envisage that efficient and effective methods be developed (bandwidth usage & power) to transmit and receive the same while maintaining quality-of-speech, especially at the receiving end. Speech coding is a technique, since the era of digitization (digital) and computerization (computational and processing horsepower - DSP) that has been a material-of-research for quite some time amongst the scientific and academic community. This paper proposes modifications in grid selection strategy in Regular Pulse Excitation section of ETSI GSM 06.10 Full Rate 13 kbps coder [6] so that there is an overall 1.8 kbps (36bits / each 20ms frame) reduction in bit-rate which can be utilized for high bit rate data hiding. These steganographic 36bits are appended in class 1B (bit d146-d181) as per 05.03[7] to finally produce bit stream of 260 bits for each frame. So, proposed modifications in GSM FR allow joint data hiding and speech coding. Watermark data like text, audio and image can be reliably transmitted at a rate of 1.8 kbps with a small effect on Objective speech quality (as can be witnessed from the obtained results with text file chosen in our analysis) and with reasonable computational complexity [1]. Here, both ETSI GSM 06.10 FR coder and proposed steganographic GSM FR coders are implemented using Simulink model in MATLAB and then Objective analysis comparison between both coders are carried out using set of tables and graphs. 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.