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possible bitrate and timeinterleaving especially in highfrequency selective fading withsuitable frequency diversity will aidthe receiver to detect COFDM

signals. COFDM standards can beused in Single Frequency

SIMULATION RESULTS

At this stage, we are ready to studysimulation results and to comparedifferent standards according tothem. First, we focus on differences

between ATSC and COFDMstandards. Next, differencesbetween

important that ATSC receiver usesa soft viterbi decoder whereasISDB-Ts one is a hard decisiondecoder. Both hard and softdecision decoders of DVB-T are

shown in this figure.As it is mentioned above,

onization equalizer is considered.But, only in COFDM standards,chan nel equalizer is used and itcorrects this error automatically. Asit can be seen if channel equalizer in

COFDM standards exists

Networks (SFN) to obtainmaximum bandwidth efficiency.

As it is mentioned above,DVB-T and ISDB-T use similar

channel coding and modulationscheme. Their main difference is intheir frame structure. ISDB-T is acomplicated standard. Itoptionallyuses time interleaving to obtain

DVB-T and ISDB-T are studied.

Comparison between ATSC and

COFDM standardsAt this point COFD Mstandards

are compared to ATSC DVB-T andISDB-T has variable bit rates, butATSC bit rate is constant. So, onlytheir bitrate near the ATSCs one(i.e. 19.3 Mbps) is studied.

Fig.9-BER of a hard decision decoder of ISDB-T in a Rayleighchannel

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