The importance of signal-to-noise ratio estimation increases due to the growth of Cognitive Radio adaptation of channel conditions based on the change in communication parameters. In this paper Mth Root Mth Power-signal-to-noise, ratio estimator algorithm is introduced and results are compared with previous work. This algorithm depends on measuring the actual received symbol plus noise power and measuring the estimated noiseless symbol power. Then calculating the difference between them to get the noise power. The Mth Root Mth Power SNR estimator algorithm is derived mathematically and tested for QPSK with additive white Gaussian noise channel model at 900 MHz using Universal Software Radio Peripheral N210.