Literature Survey for Analyzing Distortion Region in Gaussian Broadcast Channel by Bandwidth Compression and Expansion using Different Coding Schemes

Broadcasting a bivariate Gaussian source is a major problem in information theory. Consider, the bivariate Gaussian source is broadcast through a two user power limited Gaussian broadcast channel. The user receives the signal which is affected by Gaussian noise having mean zero and variance. Different coding schemes are used to analyze the region of simultaneously achievable distortion pairs at the two receivers. But explicit distortion regions are not found using existing methods. Also they are not aware of broadcasting bivariate Gaussian source with bandwidth mismatch. Recently a new coding scheme called hybrid digital analog (HDA) scheme is proposed which take both the advantage of analog transmission and digital coding. The hybrid digital analog coding scheme is suitable for both bandwidth compression and expansion (bandwidth ratio) and provides explicit distortion regions. This literature survey discusses about broadcasting Gaussian sources, Existing coding schemes and simultaneously achievable distortion regions. This paper also shows the result of distortion region for bandwidth compression by using layering with analog, superposition and Costa (HDA) coding for correlated Gaussian source.