The Detection Of Weak OFDM Signal

OFDM is one of the multi-carrier modulations , it makes different carrier modulation and a high-speed multi-channel serial data is transformed to parallel low speed sub-data streams .OFDM has high utilization ratio of spectrum,low cost and can resist the multi-path interference and frequency-selective fading. So the detection of weak OFDM signal is great significance in practical application.The paper firstly researches the standard adaptive algorithm for OFDM signal detection in low SNR. Then a new adaptive algorithm is presented. The results of the simulations have proved that the new makes the better performance.At the same time ,the paper also researches inter-class recognition of OFDM signal. A new algorithm of inter-class recognition for OFDM signal over Rayleigh channel is proposed, then we can recognized the OFDM signals from the other single carrier signals. The joint estimation of the signal to noise ratio (SNR) and the feature value based on higher order moments can realize the recognition. Simulation result s show that if the f sand f sphave been changed,the algorithm is still effective.