Improvement in Spectrum Sensing using Eigen value based sensing technique for Digital Primary Signals in Cognitive Radio using MIMO

Abstract

In present day communication wireless communication has become the most popular communication.
Cognitive radio has emerged as one of the most promising candidate solutions to improve spectrum utilization in next
generation cellular networks. The main problem is the interference between the primary signal and secondary signal.
We need a technique to deal with the problem of spectrum underutilization, which makes the birth of cognitive radio.
Energy detection can be used for spectrum sensing in cognitive radios when no prior knowledge about the primary
signals is available. And also observing that when probability of false alarm decreased with the time of probability of
detection increased. We propose new sensing methods based on the eigenvalues of the covariance matrix of signals
received at the secondary users. In particular, two sensing algorithms are suggested, one is based on the ratio of the
maximum eigenvalue to minimum eigenvalue; the other is based on the ratio of the average eigenvalue to minimum
eigenvalue.