Final Thesis

4.1.2 Multi Protocol Encapsulation, Forward Error Correction (MPE-FEC) 
The objective of the MPE-FEC is to increase the signal to noise ratio in the presence of Doppler effect in 
mobile channels. In such a way, is introduced a new additional error control level in the MPE layer. The 

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TAMK University of Applied Sciences 
Escola Politécnica Superior de Castelldefels 
Marcos Tejedor Alonso 
33 (44) 
redundancy information is calculated from the IP datagram and it is sent in a specific MPE-FEC sections. 
The MPE-FEC allows different configurations depending on the code rate that is selected. There are rates 
from 1/1, where there is no redundancy information, to ½ where for each bit of information that is sent is 
added 1 bit of redundancy. Another that are typically used are 2/3,5/6,7/8, etc. 
The MPE-FEC error protection is calculated and added separately for each single elementary stream before 
they are encapsulated into the transport stream. Using this protocol is possible to select the best rate to 
providing highly robust system. The redundancy that are introduced for this protocol can be compensated 
taking a modulation code rate lower to obtain, in the global system, a better feedback global system than if is 
used a DVB-T system without MPE-FEC with the same code rate. 
These techniques allows a highly velocity during the reception using modulations like 8k/16-QAM or 8k/64-
QAM. MPE-FEC provides a powerful immunity to impulsive noise. The receptors that are not working with 
MPE-FEC, but can decoder MPE, are capable to receive the data without any problem. 
The MPE-FEC guarantee the reception in conditions that we are working with a poor signal, and a error-
protection is introduced. The last new technique, the 4k mode for OFDM, that is next to the 2k and the 8k 
mode of the DVB-T standard, cover the needs of hand-held terminals. This mode acquires an agreement 
between transmission cell size and the capacity of the terminal.