Research Of Block Decision Feedback Equalization Algorithm In DTMB System Of Single-carrier Mode

Digital TV is recently recognized as the next generation of TV systems because of the great advantages compared with the analog TV.Digital television broadcasting has three main types:terrestrial,satellite,and cable-based digital TV.The Digital Television Terrestrial Broadcasting(DTTB) is the most complex,the widest range among them.For terrestrial digital television transmission standards,there are three main standards:ATSC(U.S.A),DVB-T(Europe) and ISDB-T(Japan) approved by the International Telecommunication Union(ITU).On August 30^th in 2006,The Chinese digital terrestrial television broadcasting standard,named "Frame structure, channel coding and modulation for digital television terrestrial broadcasting system" and standed for DTMB in English,was issued by the Standardization Administration of China(SAC),and was carried into execution on August 1^st in 2007.Therefore, research on terrestrial transmission technique according to digital television standard of our country has far-reaching meaning.The key of digital transmission system lies in carrier synchronization and channel equalization.And the most important thing is channel equalization.The role of equalization is to eliminate the effect upon the communication system performance of the multipath fading,doppler effect and additive noise problems in channel of the wireless communication.A novel block decision feedback equalizer(BDFE) algorithm based on QR decomposition,which is suitable for the single-carrier mode of Chinese Digital Terrestrial Television Multimedia Broadcasting(DTMB) standard is presented in this paper.At the beginning of this paper,the three Digital Television Terrestrial Broadcasting(DTTB) standard and Chinese DTMB standard are introduced. Secondly,this paper discusses wireless channel characteristic of DTTB system.Third, the system of DTMB standard is describe in detail,the block decision feedback equalization theory analysis in the respects of basic principles and algorithms of block decision feedback equalization are given.At last,this paper adopts BDFE algorithm relied on a QR factorization with the combination of the characteristics of the signal frame in DTMB standard.The feasibility of algorithm is verified through Matlab simulation,and the QR-BDFE algorithm is embedded in the DTMB standard C platform.According to the simulation results based on the single-carrier mode of Chinese DTMB standard,this design has well performance towards not only for static channels but also for dynamic channels,is superior to other equalization algorithm suitable for DTMB standard,and meets the performance demand of DTMB standard's receiving system.The proposed QR-BDFE algorithm combines the strength of block processing and time-domain equalization.Compared with the preceding algorithms,the QR-BDFE algorithm neither has the drawback of the DFE algorithm which is not suitable for multi-carrier systems,nor has the problem of deep-fading which the OLA-FDE algorithm is very difficult to solve.