Proposed modifications in ETSI GSM 06.10 full rate speech codec and its overall evaluation of performance using MATLAB

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. Amongst all elements of the communication system (transmitter, channel and receiver), transmission channel (carrier of information/data, also called the medium) is the most critical and plays a key role in the transmission and reception of information/data. This paper proposes some modifications in the selection process of grid positions in Regular Pulse Excitation section of 13 kbps ETSI GSM 06.10 Full Rate Speech coder so that there is an overall 1.8 kbps (36 bits / each 20 ms frame) reduction in bit-rate which can be utilized for either improving error detection and correction at channel coding or for hidden data embedding and transmission over wireless link. Both Standard GSM FR and proposed GSM FR are implemented in MATLAB. Here, Subjective and Objective analysis are carried out on a proposed system to evaluate its performance and the results obtained are then compared with the results of GSM 06.10 Full Rate coder using set of tables and graphs. As can be observed from obtained results that both PESQ and MOS scores are quite comparable for each wave files and marginal degradation of both can be witnessed with respect to decrease in codec bitrates.