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Simulation of Lithuanian Version of DVB-T System
| Content Provider | Semantic Scholar |
|---|---|
| Author | Deksnys, V. Čitavičius, Algimantas |
| Copyright Year | 2009 |
| Abstract | Economical, technical and organizational aspects of terrestrial and cable digital video broadcasting (DVB–T/C) networks rollout and switching off analog video and audio transmission in Lithuania were discussed in details before the beginning or in the early stage of these processes [1, 2]. The first DVB–T network in Lithuania was launched in 2007. After hot discussions between scientists, engineers and officials H.264/MPEG–4 AVC standard for video compression was adopted. The system parameters offered by DVB–T standard [3] were chosen taking into account the country peculiarities and long–term objectives to develop synchronous single frequency network (SFN) and mobile broadcast network in the whole country. These are: The outer Reed–Solomon coding RS(204,188, t=8); The outer convolutional interleaving with I=12; The inner error protection punctured convolutional code with coding rate 3/4; The inner block interleaver; The number of carriers – 8192 (8K mode); Modulation scheme – 64 QAM; Guard interval – 1/4. The Reed–Solomon code allows correcting up to 8 random erroneous bytes in a received word of 204 bytes. The inner coding and inner interleaving are necessary to avoid bursts of erroneous bits being fed to the Viterbi decoder. The inner interleaver consists of a combined bit and symbol interleaver, where “symbol” here refers to the bits being transmitted by one carrier during one symbol time. The requirements on guard interval length determine the number of carriers of an OFDM system. The necessary guard interval length depends on the transmitter distance in a SFN, or on the delay of natural echoes in case of a conventionally planned network. Since SFN is scheduled to be based on existing transmitter sites, it was necessary to use a guard interval of approximately 250 μs. The requirement for a guard interval determines the number of carriers: a guard interval of 250 μs can be achieved with an OFDM system with a symbol time of 1 ms and hence a carrier distance of 1 kHz, resulting in 8000 carriers in an 8 MHz wide channel. An OFDM signal is implemented using an inverse FFT. The FFT size has to be equal to 2. So 8000 carriers require N=13. The FFT size will then be 8192. Therefore maximum allowed guard interval length of 1/4 and the "8K mode" are extremely well suited both for single transmitter operation and for small and large SFN networks. The chosen combination of constellation (64 QAM) and code rate (3/4) enables the system to cope with a large variety of channel characteristics. The first Lithuanian DVB–T receiver TF–401 with Lithuanian tuner module KS–1601 [4] was designed and serial production was launched in 2007. However there are neither models nor simulation results of DVB–T systems like Lithuanian, especially having in mind Lithuanian tuner module KS–1601. We present below the main information about the known mathematical models of phase noise of different local oscillators (LO) as well as designed SIMULINK models of phase noise and of DVB–T system with the parameters identical to the chosen in Lithuania. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://internet.ktu.lt/lt/mokslas/zurnalai/elektr/z96/22__ISSN_1392-1215_Simulation%20of%20Lithuanian%20Version%20of%20DVB-T%20System.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
