الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 201 |  |  |
| | | from | 201 | | |
Abstract
Digital Video Broadcasting (DVB) systems have been evolved to im-
prove the spectrum efficiency of current multimedia communications. Over time, the demand for more interactive services with less latency and more throughput is increasing. Latest DVB systems use error correction coding techniques which cause delay in decoding of the received signal. Therefore, a new Forward Error Correction (FEC) schemes are introduced to balance between Bit Error Rate (BER) performance and decoding latency.
Recently, polar codes were proposed by Arikan to achieve opti- mum channel capacity given by Shannon theorem for symmetric bi- nary input-discrete memoryless channels. They are featured by their low encoding/decoding complexity to improve the spectrum efficiency of current multimedia communication systems. As a result, polar code is a good candidate to enhance DVB performance.
Firstly, polar codes generalization formulas and algorithms were introduced to provide more code lengths and rates to match with DVB systems code lengths without the need for shortening or punc- turing. Secondly, as the size of the kernel matrix increases, computing the Log-Likelihood Ratio (LLR) functions in successive cancellation decoder for these codes becomes mathematically more complicated.
Therefore, a new simplified general method is proposed to calculate
these LLR functions based on the schematic diagram of the selected
kernel matrix for sizes higher than 2. After that, the generalized polar codes are compared with punctured polar codes based on the 2 x 2 binary kernel matrix to select the suitable scheme for DVB systems.
Then, we compare the performance of polar and Low-Density Par- ity Check (LDPC) codes in terms of BER, encoder/decoder latencies, and throughput. The results show that both channel coding tech- niques have comparable BER. However, polar codes are superior to LDPC in terms of decoding latency, and system throughput. More- over, we present the possible performance enhancement of DVB sys- tems in terms of decoding latency and complexity when using op- timized polar codes as a FEC technique instead of Bose Chaudhuri Hocquenghem (BCH) and LDPC codes that are currently adopted in DVB standards.
Finally, according to the previous results, we propose to use po- lar codes with flexible Fully Adaptive- Successive Cancellation List (FA-SCL) decoders in DVB systems to meet the growing demand for more bit-rates. In addition, they can provide more interactive services with less latency and more throughput compared to the current FEC
techniques of DVB systems.