In cognitive radio, unlicensed users are allowed to opportunistically use a licensed band under the condition of harmless interference to licensed users. To ensure such condition, the key function of cognitive radio, spectrum sensing, needs to be reliable and fast. A new scheme of spectrum sensing where the sensing period is divided into multiple mini-slots is proposed to improve the performance of existing spectrum sensing techniques. Under the concept of multi mini-slots spectrum sensing the Primary User, PU, detection is performed for each mini-slot and the existence of PU is summarized by a fusion rule. In this paper, the multiple mini-slot concept is investigated and a comprehensive study is presented. The simulation results show that the more slots each sensing period is divided into, the higher the accuracy of detection becomes. The computational time is slightly increased as well, but it has no significant effect on the overall performance. The paper evaluates its performance against other conventional techniques. The results show our technique performs the best with the highest probability of detection. The computational time is kept short, similar to Energy Detection, ED.