A spectrum sensing model for continuous transmission in cognitive radio network

Cognitive radio (CR) has been proposed as a promising solution to the spectrum scarcity problem. In such solution, unlicensed secondary users (SUs) have the challenge of using the best spectrum´s opportunities without interfering with the operation of licensed primary users (PUs). Hence, many researches have been carried out to maximize the CR throughput under the restriction of avoiding interference on PU network. However, most of these studies have considered that the transmission of SUs is not allowed within the sensed band during the sensing period. This consideration leads the CR to underutilize the available spectrum while sensing the radio frequency environment. Although current technologies don´t allow for transmission and sensing at the same time, we prove in this paper that it is possible to sense and receive at the same time. We propose an extension for the traditional energy detection technique that allows the CR to sense the spectrum and decide about the PU presence even while other SUs are transmitting in the sensed spectrum band. Furthermore, we show that the proposed spectrum sensing model supports secondary-to-primary power ratio of about 31 dB for the IEEE 802.22 standard specifications.