Synchronization Algorithm Research Based On Dvb - T2

The DTTB(Digital Terrestrial Television Broadcast) is one of the three dominatingdigital TV standards in the world today, it has a lot of advantages on withstandingmultipath effect, covering a big area, and its equipment on users’ end is cheaper thanothers, so DTTB has gotten great attention from all countries. There are fourinternational standards in the world, and DVB-T, which was developed by the EuropeanTelecommunications Organization, is the most popular application. DVB-T2whoseperformance is greatly enhanced is the upgrade system, deployed in Europe, Asia,Africa and other countries quickly.It is unanimously affirmed by the majority of users.Therefore, the study of key technologies in DVB-T2is of great significance.The same as DVB-T, The DVB-T2has adopted COFDM modulation system.Because of good capability on withstanding multipath effect and high spectrumefficiency, COFDM has applied in most of communication systems. But it has somedisadvantages, such as being sensitive on synchronous error, tending to emerge ISI andICI, and so on. So it is very important to study the synchronization technology for thedesign of the receiver. DVB-T2has more parameters, higher bandwidth efficiency, moredata per second. It is a big challenge to get the correct synchronization quickly.This thesis focuses on timing synchronization and carrier synchronization of thereceiver in the DVB-T2system, and put forward a reasonable solution onsynchronization technology. Firstly, it introduced the DVB-T2frame structure and thephysical resource characteristics about synchronization. Because of the rationalutilization of physical resource, it has reduced the overhead of the synchronizationscheme. This is also a feature of this article. This thesis also briefly describes the basiccharacteristics of the multipath channel of the terrestrial broadcasting, and it analysesthe small-scale fading effects in the DVB-T2channel model. Then it calculates theimpact of the synchronization error (timing synchronization offset, carrier frequencyoffset) on the transmitted signal, quantify the loss of SNR in different situations.According to the physical resource characteristics, this paper presents a synchronoussolution for the DVB-T2system. It analyses the synchronization algorithm performance based on the P1symbol, cyclic prefix and pilot. The synchronization algorithms containframe timing synchronization, symbol timing coarse synchronization, symbol timingfine synchronization, the estimation of an integer multiple of carrier frequency offsetand the estimation of small multiple of the carrier frequency offset. Because the timingcoarse synchronization has a great influence on the performance of the synchronization,this paper focuses on the advantages and disadvantages of the ML algorithm and aseries of the improved algorithm, and has proposed a synchronization scheme in a lowSNR environment.The results of these simulations show that the proposed synchronization schememeets the requirements. It capture the P1symbol(frame head) correctly in the Roycechannel when the SNR is equal to2dB, and the symbol timing estimation can fullysatisfy the system when the SNR is equal to5dB. The coarse synchronization algorithmis MMSE, it is easy to compensate the offset because the timing error between [-30,35].These two timing synchronization can cascade to estimate time offset because they havedifferent synchronization resources, so that we can not only improve the estimationaccuracy, but also reduce the complexity. The MSE of The carrier frequency offsetestimation is below10-5when the SNR is greater than-2dB, it has a great advantage ofthe subsequent channel estimation process.