Abstract:

Based on cyclic autocorrelation, an algorithm of blind recognition of orthogonal frequency division multiplexing (OFDM) signals in the multi-path fading channels is proposed. Derivation of the cyclic autocorrelation characteristics for OFDM signals with a cyclic prefix in the multipath fading channels is done, it verifies that the cyclic autocorrelation of OFDM signals will appear peaks at a certain time delay, while single-carrier signals is without peaks. So, OFDM signals can be recognized from single-carrier signals in multipath fading channels. The new recognition algorithm eliminates the preprocessing tasks, such as symbol timing estimation, carrier and waveform recovery, and signal to noise ratio estimation as well. Also, the proposed algorithm is with low computational complexity and high recognition rate. Simulation verifies that the proposed recognition algorithm is correct and efficient.

Key words: modulation identification, cyclic autocorrelation, multipath, orthogonal frequency division multiplexing