Sharif Digital Repository

Network coding, as a novel technique, suggests that the intermediate nodes of a network can combine independent flows to optimize the usage of a shared communication channel. Also, distributed source coding, exploits the joint statistics of correlated information sources to reduce the volume of transmitted information. Surprisingly, it has been shown that linear network codes are able to compress correlated sources. In this project, we have focused on this problem, i.e. joint distributed source and network coding. We have two important contributions with different directions. First we give a practical design for joint coding. Second, we use an evolutionary approach to find the best placement... 

The two central topics of information theory are the compression and the transmission of data. Shannon, in his seminal work, formalized both these problems and determined their fundamental limits. Since then the main goal of coding theory has been to find practical schemes that approach these limits.Polar codes, recently invented by Arıkan, are the first practical codes that are known to achieve the capacity for a large class of channels. Their code construction is based on a phenomenon called “channel polarization”.
Since the performance of polar code degrades when the block length is small, several kinds of Reed – Solomon concatenation is considered in order to improve the... 

The coding and compression of information sources with special probability distribution is the center of concentration of researchers in this field in the last decades. In this dissertation, after a concise introduction to source coding, we focus on the universal source coding and data compression from an algorithmic and information theoretic point of view. First we introduce the fundamental concepts of source coding and data compression. Then, we analysis some algorithms on integer coding and verify their universality and asymptotically optimality. Usually statistics of information sources is not available in communication systems and storage devices, so that applying universal source... 

Polar codes were introduced by Arikan in 2009. These codes are the first family of codes that with low encoding complexity and successive cancellation decoder, can achieve the channel capacity. Polar codes, at first were implemented for channel coding, but in 2010 performance of these codes in binary and q-ary alphabet source was studied. It is shown that these codes can perform efficiently in channel coding and source coding. On the other hand, one of the most important continuous sources are Gaussian sources. Due to the importance of Gaussian sources and good performance of polar codes, we try to evaluate the performance of these codes in Gaussian sources. Note that, these codes have... 

In most stochastic models with uncountable cardinality of sample space with non-trivial probability measures, the inherent information is infinite. The continuous-valued random variables and continuous-domain random processes are among such objects. Therefore, a fidelity criterion must be defined between the stochastic subject and its estimated version. Although there are some criteria for of stochastic continuous signals, based on quantizing the signal in both time and amplitude domains, we are going to define a criterion which is for stochastic processes in bounded time domain. Next, the criterion will be expressed in general sources perspective and the optimum rate of coding will be...