  Under a low Signal-to-Noise Ratio (SNR), the Orthogonal Frequency-Division
Multiplexing (OFDM) signal symbol rate is limited. Existing carrier number
estimation algorithms lack adequate methods to deal with low SNR. This paper
proposes an algorithm with a low error rate under low SNR by correlating the
signal and applying a Fast Fourier Transform (FFT) operation. By improving
existing algorithms, we improve the performance of the OFDM carrier count
algorithm. The performance of the OFDM's useful symbol time estimation
algorithm is improved by estimating the number of carriers and symbol rate.
