Biblio

In this paper, we have considered the broadcasting of a memoryless bivariate Gaussian source over a Gaussian broadcast channel with respect to bandwidth compression. We have analysed the performance of a hybrid digital-analog (HDA) coding system in combination with joint source channel coding (JSCC) to measure the distortion regions. The transmission advantages due to the combination of both the analog and digital techniques, a class of HDA schemes that yields better performance in distortion is discussed. The performance of source and channel coding for the possible better outcome of the system is measured by employing Wyner-Ziv and Costa coding. In our model, we have considered the upper layer to be a combination of a hybrid layer in the sense of both the analog and digital processing is done. This is executed in presence of quantization error and performance of the system is measured with two conditions: 1) HDA scheme with quantization scaling factor α = 0, i.e. the input of the channel have only the analog information which is considered as the scaled quantization error βS 2) The analog information from the first layer S is suppressed by setting error scaling factor β = 0 and 3) Inclusion of recursive mode with JSCC in each of the three layers for the possible better outcome is considered here.

GSM network is the most widely used communication network for mobile phones in the World. However the security of the voice communication is the main issue in the GSM network. This paper proposes the technique for secure end to end communication over GSM network. The voice signal is encrypted at real time using digital techniques and transmitted over the GSM network. At receiver end the same decoding algorithm is used to extract the original speech signal. The speech trans-coding process of the GSM, severely distort an encrypted signal that does not possess the characteristics of speech signal. Therefore, it is not possible to use standard modem techniques over the GSM speech channel. The user may choose an appropriate algorithm and hardware platform as per requirement.