JPL's Wireless Communication Reference Website

Chapter: Network Concepts and Standards
Section: Broadcast Systems, Digital Video Broadcasting (DVB), Digital Terrestrial Television Broadcasting (DTTB)


DTTB System Performance

Contributed by Paul G.M. de Bot and Flavio Daffara


BER of 4-QAM with concatenated coding on a Rayleigh channel, for different inner code rates R


BER of 64-QAM with concatenated coding on a Rayleigh channel, for different inner code rates R

The Bit Error Rate curves are given for a few modulation / code combinations on a Rayleigh channel. It can be seen, that the required SNR ranges from less than 5 to more than 25 dB, depending on the transmission mode.

Co-existence with Analogue PAL

Furthermore, we should notice that in case of co-channel interference (CCI) from PAL, the receiver will give sufficiently low error rates for signal-to-interference ratios as low as 0 dB (depending on modulation/coding). This remarkable result can be explained by the fact that even with an SIR of 0 dB, most of the OFDM carriers are subject to a narrow-band SIR of more than 20 dB, since the interfering power is concentrated on only a limited number of OFDM carriers. The error correcting codes are easily capable of correcting the errors made in this limited number of interfered OFDM carriers. Its ruggedness towards CCI from analog services is one of the major advantages of OFDM.

Effective Bit Rate

The net bit rate can be calculated from the net symbol rate, and depends on the modulation and coding.


Table: Net Bit Rate (in Mbit/s) of a Typical DTTB System (see below), for different modulation schemes and inner convolutional code rates R.



JPL's Wireless Communication Reference Website © Paul G.M. de Bot, Flavio Daffara and 1993, 1995.