# Integrated DVB-X2 Receiver Architecture with Common Acceleration Engine
## 2 System Description
### DVB-T2, DVB-C2, and DVB-S2 Standards  
DVB-T2 provides six FFT sizes up to 32K FFT, seven diverse GIs, and four OFDM modulation-based modulation schemes up to 256-quadrature amplitude modulation (QAM). In addition, it offers a concatenated LDPC and BCH code with various code rates. DVB-C2 provides 4K FFT sizes, two GIs, five OFDM modulation-based modulation schemes up to 4096-QAM, and the LDPC/BCH code. DVB-S2 provides four modulation modes such as quadrature phase-shift keying (QPSK), 8-PSK, 16-amplitude and PSK (APSK), and 32-APSK. It also offers the LDPC/BCH code with various code rates. Table 1 summarizes the DVB-T2, DVB-C2, and DVB-S2 features. Figure 1 shows block diagrams of DVB-T2, DVB-C2, and DVB-S2 receivers.  
Figure 2 shows the frame structure of DVB-T2, DVB-C2, and DVB-S2. In DVB-T2, a super frame consists of up to 255 T2 frames. A T2 frame consists of a P1 symbol, a P2 symbol, and data symbols.  
The P1 symbol as a start signal of the frame is designed to be suitable for estimating time synchronization and coarse fractional frequency synchronization, and it carries 7-bit basic system  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Mode** & **DVB-T2** & **DVB-C2** & **DVB-S2** \\ \hline Input Interface & Multiple TS and GSE & Multiple TS and GSE & Multiple TS and GSE \\ FEC & LDPC/BCH & LDPC/BCH & LDPC/BCH \\ \hline Code Rate & 1/2, 3/5, 2/3, 3/4, 4/5, 5/6 & 1/2, 2/3, 3/4, 4/5, 5/6, 8/9, & 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, \\ Interleaving & Bit, Cell, Time, Freq. & Bit, Time, Freq. & Bit \\ Modulation & QPSK, & 16-QAM to & QPSK to 8-PSK, 16-APSK, \\ Schemes & 16-QAM to & 4096-QAM & 32-APSK \\ Modulation & OFDM & OFDM & Single Carrier \\ Guard Interval & 1/4, 1/8, 1/16, 1/32, 1/128, & 1/64, 1/128 & - \\ FFT Size & 18, 2K, 4K, 8K, 16K, 32K & 4K & - \\ Pilots & Scattered, Edge, Continual, & Scattered, Edge, Continual, & 36 pilot symbols \\ P2, Frame-closing & & Preamble & \\ \hline \hline \end{tabular}
\end{table}
Table 1: DVB-T2, DVB-C2, and DVB-S2 features.  
Figure 1: Block diagrams of (**a**) DVB-T2, (**b**) DVB-C2, and (**c**) DVB-S2 receivers.  
Figure 2: Frame structures of (**a**) DVB-T2, (**b**) DVB-C2, and (**c**) DVB-S2.  
information such as FFT size and multiple input single output (MISO) availability. The P1 symbol is a 1K OFDM symbol modulated into binary PSK (BPSK), and has a C-A-B structure of two GIs back and forth. The P2 symbol provides Layer 1 signaling information, and consists of an L1 pre-signaling and an L1 post-signaling. The L1 pre-signaling transfers peak to average power ratio (PAPR) availability, L1 post-signaling related information, pilot patterns, a number of data symbols, a number of T2 frames, and GI information. The L1 post-signaling contains physical layer pipe (PLP) and future extension frame (FEF)-related information. A C2 frame consists of a preamble symbol and data symbols. The preamble symbol includes L1 signaling part 2 data, which provide all of the information needed for a receiver to access an L2 signaling and PLPs in the C2 frame. A preamble header is composed of 32 OFDM cells, which are placed in front of the L1 time interleaving block in each of the preamble symbols. In DVB-S2, each frame is made up of a PLHEADER and slots, in which DTV broadcasting contents are actually transferred. The PLHEADER consists of the start of a frame (SOF) symbol and a physical layer signaling (PLS) code symbol. The SOF symbol is sent at the beginning of the frame. The PLS code symbol includes a MODCOD field specifying the modulation and code type, and the type field that specifies the FECFRAME length (64,800 bits or 16,200 bits) and the presence/absence of pilots. The PLHEADER is composed of 90 symbols, and each slot is also composed of 90 symbols. The number of slots, S is determined by the modulation scheme and the size of code blocks. The pilot blocks, consisting of 36 symbols in every 16 slots, are transferred.