M.Sc. Tezi Görüntüleme
As a result of recently technological developments and increase in the amount of services provided by digital communication systems, error correction codes gain great amount of importance.
Error correction codes are a means of including redundancy in a stream of information bits to allow the detection and correction of symbol errors during transmission. The birth of error correction coding showed that Shannon�s channel capacity (information theory) could be achieved when transmitting information through a noisy channel. Turbo codes are the newest and a very powerful form of error correction codes that it takes the performance of practical coding even closer to Shannon�s theoretical specifications. This new code yields very good performance with relatively simple component codes and large interleavers in combination with an iterative decoding process.
The dissertation specifically describes the structure of turbo codes, gives the performance of turbo codes in additive white Gaussian noise (AWGN) channels and thus, determines the factors that influence the performance of turbo codes in AWGN channels. Therefore, initially, turbo encoding and decoding process is studied carefully and great amount of information about the iterative decoding technique (MAP) is given. Then, by changing the factors that influence the performance of turbo codes in AWGN channels, various simulation results are obtained.
Keywords:Parallel Concatenation Codes, Recursive Convolutional Encoding, Nonuniform Interleaving, Iterative Decoding Algorithm (MAP).