LDPC encoded pilots for iterative receiver improvement
Turbo and low density parity check (LDPC) codes show performances approaching Shannon capacity. This thesis proposes a novel iterative channel estimation and LDPC decoding scheme where the pilot symbols are encoded and can be used for both channel estimation and decoding using soft iterative receiver. To achieve this objective, systematic LDPC codes are employed so that pilot symbols can be encoded as data. In this way, initial channel estimation can be made before decoding by using the systematic coded pilot symbols. In addition, the known pilot symbol positions have higher reliability than data and can improve the initial decoding significantly. Using simulations it is shown that the decoding capability of the receiver improves significantly and ultimately LDPC decoder converges much early compared to the case where there are no coded pilots. Moreover, passing soft decoded values to the iterative receiver the coding gain improves also in comparison to the case when passing hard decoded values. (Abstract shortened by UMI.)
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering.