비균일 오류 확률 기반 다중 밴드 FTN 전송 기법 연구

Abstract

In next generation satellite broadcasting system, requirement of high throughput efficiency has been increasing continuously. To increase throughput efficiency and improve bit error performance, FTN (Faster Than Nyquist) method is employed in new satellite standard, DVB-S3 (Digital Video Broadcasting - Satellite - Third Generation) system and FOBTV(Future of Broadcast Television) system.

FTN is a method of transmitting information at a rate higher than the allowed Nyquist limit. In order to improve the transmission efficiency by applying the FTN method, according to increasing the interference rate. However, performance degrade arising from ISI(Inter-symbol interference). The other attempt is MIMO(Multiple Input Multiple Output)-FTN transmission method, which combines the MIMO and FTN methods to improve throughput, can maximize the improvement of throughput, however its decoding method and removal of interference is difficult, the research about which is under developed yet. And MIMO-FTN method requires accurate channel estimation for each channel, yet does not improve performance compared to the SISO (Single Input Single Output)–FTN method.

Therefore, in this thesis, proposed an unequal error probability (UEP) based multiband FTN transmission method that transmits the FTN interference differently applied to each band of multiband to each one. This method, by classifying band depending on the importance of the encoded bits of a channel encoder, improves performance in the same overall interference by allocating less FTN interference to the band to which important bits belong and more FTN interference to the band to which unimportant bits belong.

Lastly, proposed an OFDM(Orthogonal Frequency Division Multiplexing)-FTN method based on UEP algorithm in multipath channels as in massive mobile communication networks such as 5G. The OFDM method divides data into multiple carrier signals, and multiplexes and transmits them by adding orthogonality to minimize the interval between divided carrier signals. Since OFDM with high spectrum efficiency is efficient in a frequency selective fading channel environment and a multipath channel environment, it can maximize the band efficiency by applying the FTN method and also guarantee the performance in multipath channels.