Abstract:

An extension technique from orthogonal frequency division multiplexing（OFDM） named overlapped frequency division multiplexing (OVFDM) is presented. Compared to the orthogonality between the carriers in OFDM system, OVFDM focus on the general frequency spacing of subcarriers. The method proposed not only improves the spectral efficiency of OFDM system but generates the coding constraint relationship. The detection algotirhm in the receiver is actually a frequency domain maximum likelihood sequence detection (MLSD) after using window function, and the complexity is limited moreover. Because OVFDM is not depend on the orthogonality among subcarriers but on the convolution constraint relationship among them, its spectral efficiency could be improved optionally. And the system’s spectrum and power are more effective because there exists no cyclic prefix. Analysis and simulation verify the validity of this theory.

Key words: orthogonal frequency division multiplexing, overlapped frequency division multiplexing, maximum likelihood sequence detection