Babu, B Theresh and Sharma, G V V
(2019)
Modem design for DVB-S2.
Masters thesis, Indian institute of technology Hyderabad.
Abstract
The Need of providing high quality video transmission services like Direct-To-Home services was becoming a hot topic in the area of wireless communication. This imposes a huge demand in terms of high data rate and high quality of service in satellite video transmission inflicting strict constraints on the power and bandwidth efficiencies of the Physical Layer (PHY-layer) wireless communication systems. Much more extensive research was going on to fulfil these requirements. DVB-S2 standard was one among them. DVB-S2 standard is a 2003 version under the DVB project. In this, channel capacity has been achieved by employing LDPC codes as inner encoder and BCH codes as outer encoder. Which will meet the demands of channel capacity to near shannon limit. The total system of Channel encoder with BCH+LDPC coding, efficent mapping schemes of PSK and APSK, efficient transmission design techniques like Interleaving,Physica Layer Framing and Pulse shaping ,and a robust receiver synchronization block which will gives to hightly reliable communication over a noisy channel. In this thesis, main focus is on the implementation of modulator, demodulator,Channel Encoder and Decoder techniques as independent modules in particular for each transmitter block suitable demodulator block which is identified in the DVB-S2 standard will be designed and verified using the numerous simulations.Throughout the whole thesis wherever possible, all the subblock equations have been optimized and the key equations taken from various standard papers for implementation have been given in more understandable format. By using Berlekamp-Massey algorithm for BCH Decoding and standard BCH Encoding process, the perfomance of BCH codes was analyzed using SNR vs BER graph. For the case of LDPC codes message passing algorithm was used for decoding and standard encoding used , the performance of same is analyzed with SNR vs BER graph. The performance of PSK, APSK modulation schemes are analyzed using SNR vs BER graph simulations with an optimized way of demapping. The Efficient Transmitter Design Techniques listed in the standard i.e Interleaver, Physical Layer Framing and Pulse shaping are analyzed with SNR vs BER graph by taking QPSK mapping scheme. In Receiver Synchronization, each synchronization block have been implemented independently with BPSK/QPSK mapping schemes and analyzed with SNR vs BER performance. Results of all subblocks have been verified using the standard document
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