| Channel coding is a technique used to combat channel impairments in digital and wireless communication systems, and turbo code is one of the latest channel coding technologies. This thesis presents a review of turbo encoder structures, decoding algorithms, and a discovery of a scaling coefficient of the extrinsic information in the iterative decoding process that dramatically changes the convergence speed and error performance of turbo codes. With the knowledge that this coefficient is tunable in nature, a new design of iterative turbo decoder based on this tuning factor and error detection is proposed to optimize the error performance. Simulations of single and multiple tuning factors decoding schemes are performed, and the results show that superior performance can be obtained when the tuning factor method is applied. |
