Performance Comparisons for Serial Concatenated Block Convolutional Codes when Sequentially and Iteratively Decoded PDF Download

Author: Dana Nazir Dannan
Publisher:
ISBN:
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Languages : en
Pages : 178

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Book Description
Serially Concatenated Codes, a concept building on classical concatenated codes and parallel concatenated codes known as "Turbo Codes", have been studied for ma ny years. One of the most important forms of serial concatenated codes that was first discovered by Forney [14], consists of a simple convolutional code as an inner c ode and a Reed_ Solomon code as an outer code, and the decoding for this coding scheme is done sequentially, using each decoder once. In this thesis, other powerful linear block codes such as Hamming and BCH codes were considered. Simulations were done for three models with and without an inte rleaver and for different block lengths. Comparative study of the three models w as done in order to find out how the block code may affect the performance. The simulation results showed that both Hamming and BCH codes give the same performa nce for the same values of Energy bit to Noise ratio (EbNo), but a Reed_ Solomon model gives a good performance. In the second part of the thesis, other ways of serial poncatenations were appli ed but here the used decoder will be changed from sequential decoder into iterat ive decoder. The new iterative decoder consists of an outer (SISO), and an inner block decode r that corresponds to the used block encoder, simulation results showed a very b ad performance comparing to the previous models. A new way of serial concatenati on was done, by connecting a block encoder serially to an (SCCC) in the encoder side, and for the decoder side, a block decoder was serially connected to the it erative decoder. Simulation results showed that the new way of concatenating gives a very good performance comparing to the first models for different block codes. Important comparisons were also done in order to see the effect of the block codes when they are modified to a S erial Concatenated Convolutional Codes (SCCCs). Results showed that both Hamming and BCH codes give approximately same performance that is obtained by the equiv alent (SCCC). But when using the Reed_ Solomon code, a very good performance was achieved comparing to all other models, even when compared to Serial Concatenat ed Convolutional Code (SCCC).