Research On Overlapped Frequency Division Multiplexing System

In wireless communications system, diversity is a kind of effective technique to resistmulti-path fading and channel interference. Collaborative communication, which combinesdiversity and relay communication technology, can improve the reliability of the network.OVFDM (Overlapped Frequency Division Multiplexing) can obtain higher efficiency byoverlapping spectral and a better performance comparing with higher order modulation underthe same spectral efficiency. OVFDM and system performance combining with collaborativecommunication are mainly studied in this thesis. The following are the main work:Firstly, diversity and merging technology are introduced, and the basic principle ofcollaborative communication, AF and DF of fixed relay model are introduced in detail.Secondly, the communication model of OVFDM system is constructed, and the spectrumefficiency and receiver structure of this system are studied. The bit error rate of OVFDMsystems and higher order modulation with the same spectral efficiency are simulated andanalyzed in an additive white Gaussian noise channel. The simulation results show that theBER performance of the system is improved when the overlap coefficient is3.Thirdly, zero-padding and cyclic-prefix, which are the two kinds of method to eliminateinter-symbol interference, are discussed from the perspective of signal processing.Finally, combining OVFDM with AF and DF is put forward in this paper. The bit errorrate of the new systems and traditional collaborative model are compared with. Thesimulation results show that the performance of OVFDM combining with AF improves undersome conditions, while the new system based DF improves obviously.