Continuous Spectrum Sensing and Transmission in MIMO Cognitive Radio Network

In order to fit the demand of future communication systems, cognitive radio is a candidate solution for 5G systems. Data transmission of secondary users in classical cognitive radio networks is not allowed within the sensed band during the sensing period resulting in underutilization of the available spectrum. Aiming at a higher network throughput than in classical approaches, the spectrum sensing is performed at the receiving node of the secondary network instead of the transmitting node. This allows the transmitter to use the available band until notified by the network of the presence of a primary user. In this paper, we extend this concept to a MIMO spectrum sensing with arbitrary numbers of primary and secondary transmitters as well as of sensors of the secondary receiver. Our contributions are the theoretical approximations that help to compute the detection and false alarm probabilities valid only for a large number of samples of Gaussian signals using energy detection technique. Large quantity of samples is needed to compensate interference of secondary signals in the sensing process. The proposed theoretical model is validated via various Monte Carlo numerical performance evaluations assuming Rayleigh fading communication channels.