Transmission methods for wireless multi carrier systems in time-varying environments
Auch gedruckt in der BibliothekZ: J-H 14.524 ; W: W-H 12.090
FakultätFakultät für Ingenieurwissenschaften und Informatik
Ressourcen- / MedientypDissertation, Text
Datum der Freischaltung2011-12-13
Fast time-variant and frequency selective radio channels lead to significant challenges for the design of wireless data transmission systems. A scenario where such difficult channels occur is the data link to a high speed train. In this work, we present some transmission methods that are particularly suited for fast time variant and frequency selective channels. As a basis, we use a combination of orthogonal frequency division multiplexing (OFDM) and M-ary frequency shift keying (MFSK). By using OFDM, it is possible to avoid inter symbol interference so that there is no need for a complex equalizer even for high data rates. Due to the fact that MFSK can be detected noncoherently, OFDM-MFSK-based modulation schemes do not rely on exact channel estimation which leads to very robust transmission methods. After introducing several OFDM-MFSK-based modulation schemes, we present methods that can improve the detection by using iterative receivers and multiple symbol detection. We also show how the performance can be improved by a proper matching of the bit mapping and the channel code. Furthermore, we show that the introduced modulation schemes can be regarded as subspace-based information transmission.
LizenzStandard (ohne Print-On-Demand)
LCSHOrthogonal frequency division multiplexing