FREQUENCY HOPPING AND ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING COMMUNICATION SYSTEM

摘要

PURPOSE: A frequency hopping(FH)/orthogonal frequency division multiplexing(OFDM) communications system is provided to modulate transmitting data with an OFDM method and to apply an FH to the transmitting data, to divide single symbol into many subcarriers so as to improve system distortions caused by jammings generated when the subcarriers are transmitted. CONSTITUTION: A serial to parallel(S/P) converter(402) inputs serial transmission data to convert the data into parallel transmission data. An N-point complex inverse fast Fourier transform(IFFT) block(404) inputs the parallel transmission data to apply an inverse IFFT to the data, and modulates the data into predetermined subcarriers. A parallel to serial(P/S) converter(406) serially converts the modulated parallel data. A guard interval insertion block(408) inserts a guard interval for removing frame interferences and symbol interferences caused by interferences of the subcarriers into the serial data. A digital to analog(D/A) converter(409) converts the guard interval-inserted serial data into consecutive baseband signals. A mixer(103) mixes the baseband signals with carrier frequencies synthesized on the basis of frequency hopping(FH) codes, and outputs the mixed signals.