The dynamic spectrum allocation is important to improve spectrum efficiency usage of available radio spectrum. Cognitive radio has emerged as a solution to dynamic spectrum access, due to its adaptability and re-configurability. The main problem of cognitive radio is how the secondary users can detect the holes in the frequency band of the primary users. Spectrum sensing is the main feature of cognitive radio technology. Finding a more accurate and efficient spectrum sensing technique is the core of cognitive radio technology to develop dynamic resource management in future wireless networks. A spectrum sensing based on the auto correlation technique provides performance improvement at very low SNR over the energy detection technique. In this paper, we show the autocorrelation spectrum sensing features over energy detection spectrum sensing technique. Analytical and Simulation results are performed in a non-fading and a fading environment as well. The results show that the autocorrelation technique has enormous superiority in performance over that of the energy technique.