Research And Application Of Key Technology Of Digital Television Terrestrial Multimedia Broadcasting System

As One of three Digital Television transmissionmode, Digital TelevisionTerrestrial Broadcasting (DTTB) is the most complicated representationas a result of theawful transmission environment, and in the application of mobile and portable. Because of the uncertainty of the radio channel, the traditional analog TV vulnerable to various distortion.Digital TelevisionTerrestrial Broadcasting (DTTB) which withOrthogonal Frequency Division Multiplexing (OFDM) modulation technology, not only has the strong robust to multipath distortion but also improve the utilization of the radio spectrum, and make it possibleto receive high-quality signalsstability in the mobile state.Digital TelevisionTerrestrial Broadcasting is a important part of broadcasting system. OnAugust 18,2006, China promulgated theChinese standards named<Framing Structure, Channel Coding and Modulation for Digital Television Terrestrial Broadcasting System>, and from August 1,2007 formally implemented.Nowadays, there are four terrestrial broadcasting standards which have been admited as international standands by International Telecommunication Union (ITU) including DVB-T(Europe) and ISDB-T (Japan), ATSC (U.S.A) and DTMB(China).The aim of this article is to research communication technology in DTMB system, as well as the application ofsingle-frequency network in Channel DS-21 of Jiangsu.DVB-T (Digital Video Broadcasting) specification is one of the DTTB standards. It who useCOFDM (coded orthogonal frequency division multiplexing)technology, has good appraisement in digital television broadcasting industry. DVB-T gives a good performance in the application of mobile and portable through insertinga lot of pilot signals andguard intervals.DTMB (Terrestrial Digital Multimedia Television Broadcasting) communication system uses TDS-OFDM (Time Domain Synchronous-Orthogonal Frequency Division Multiplexing) modulation technique, which is orthogonal frequency division multiplexing modulation with PN sequence as guard interval.DTMBhasthe advantage of higher utilization of the radio spectrumthat the PN sequence at the receiving end is known and channel estimation and equalization using correlation of PN sequence, as well as a disadvantage of higher complexity algorithm.This paper researched the Transmission technologyof DTMB standards and the characteristic of PN sequencewhen focusing on channel estimation with PN sequence for the two standards.Alow-complexity channel estimation method without iteration and decisionfeed-back for TDS-OFDM systems is proposed, then we can use the PN-based correlation with insufficient Preamble toestimate the long delay multi-path precisely.Finally it givesthe analysis of the performances according to the software simulationresults.This paper, in addition, discussthe application of the single frequency network (SFN) of DS-21 channal of DTMB (Terrestrial Digital Multimedia Television Broadcasting) in Jiangsu.SFN will Greatly improve the spectrum utilization under the condition of limited radio spectrum while SFN will enhance the delay multi-path and cause trouble of networking. This paper researched the theory of SFN technologyand networking design. Considering of interferingfrequency in Jiangsu and condition, we work out the designfor networkingproject with lots of transmitting stations available.Then we figure out the trouble of networking in interference areaeffectively by using a lot of network optimizationTechnologyduring the construction, so far, we haverealized effectivecoveragein 13 cities and 14Counties in Jiangsu.