# Optimized Polar Codes as Forward Error Correction Coding for Digital Video Broadcasting Systems
## 6 Proposed DVB System Using Polar Codes  
Digital Video Broadcasting (DVB) is a collection of standards produced by European Telecommunications Standards Institute (ETSI) under the auspices of the DVB project. It aims to unite the specifications of the devices used to transmit and receive multimedia via cable (DVB-C), terrestrial (DVB-T) or satellite (DVB-S). DVB Systems use different modulation schemes and several channel coding techniques, inner and outer coding. Inner coding is utilized as the main error correcting coding like Turbo codes or LDPC codes. However, outer coding is utilized to remove residual errors after inner coding like Reed-Solomon (RS) or BCH codes. Over the years, DVB systems are regularly upgraded to meet the increasing demand for more bandwidth/bitrate and new advanced interactive services. The FEC schemes used in DVB systems have evolved over the last two decades. In the beginning, DVB systems were using convolutional code for inner coding and RS coding for outer coding [43; 44; 45]. As the size of carriers for broadcasting increased, the need for a powerful FEC scheme was recognized. Moreover, DVB created another standard in 1999 called Digital Video Broadcasting-Digital Satellite News Gathering (DVB-DSNG) [46], which added and standardized 8 PSK and 16 QAM modulation (more efficient than QPSK but requiring more link margin) to be used for professional applications especially news gathering live show. However, the DVB-DSNG does not support any enhancement in channel coding, which is applied to protect information bits from errors and provide FEC with different code rate ratios. Therefore, LDPC and BCH are adopted by the DVB committee as the inner and outer coding, respectively. These codes are now part of the DVB-S2, DVB-T2, DVB-C2, and DVB-S2X standards [38; 47; 48; 49]. The increase of the demand on interactive services leads to more need for optimizing more aspects like decoding latency and complexity. In the proposed enhanced model, as shown in Figure 12, optimized polar code is introduced into DVB systems to replace both BCH code and LDPC code in the FEC coding block in these systems standards, where optimized polar codes can achieve a comparable error performance to LDPC code  
Figure 11: Throughput versus \(E_{b}/N_{0}\) for LDPC and optimized polar codes using short frame with \(N=16,200\) and different code rates \(R\) in DVB-S2. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Code Type** & **Polar Code** & **LDPC Code** \\ \hline BER Performance & Good & Good \\ Encoder Latency & Low & Low \\ Decoder Latency & Low & High \\ System Throughput & High & Low \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Qualitative simulation results summarization. with less latency and more throughput, and as polar codes are not suffering from error floor [26], hence no need to use BCH for outer coding. To make sure of that, a comparison between simulation results of LDPC code concatenated with BCH code as described in DVB-S2 standard [38; 50] and optimized polar codes using AFF3 CT simulator has been executed. The simulation setting is compliant with DVB-S2 standard [38] with release (ETSI EN 302307-1) as an example for comparison. Figure 13 shows the packet error rate (PER) versus \(E_{s}/N_{0}\) for coded blocks of 64,800 bits (normal frame) with QPSK modulation same as in DVB-S2 standard for different code rates in the AWGN channel. From these results, it is concluded that optimized polar codes can achieve a comparable error performance to BCH+LDPC where the difference ranges between 0.3 dB to 0.6 dB. Table 6 presents measured average latency comparisons using AFF3 CT simulator between LDPC and BCH codes as used in DVB-S2 and optimized polar code for normal frame at QEF points for reception conditions on an AWGN channel for different mentioned code rates. According to these latency simulation results, optimized polar code overall processing time is smaller than LDPC and BCH codes, with a powerful decoding latency enhancement.