Measuring noise effect on the signal in channel is very much required to have an high efficient transmission. There by estimating the ratio of signal to noise, mean square error and bit error rate is necessary. In this paper we have developed two algorithms, first to estimate Signal to Noise ratio (SNR) with respect to Gaussian noise in the channel and then by incrementing power of the signal corresponding SNR is obtained. Mean Squarer Error (MSE) of the signal is also calculated for the same incremental values of power. Second algorithm obtains BER of the channel, to reduce this error rate power is increased until an acceptable BER of the channel is found for varies M of QAM technique in OFDM system. Simulation results of SNR, MSE and BER for incremental power has been shown using MATLAB.