The rapid growth of wireless communication systems around the world has led to a significant demand for more radio spectrum resources. Radio spectrum regulators are facing several challenges due to spectrum scarcity caused not only by increased demand but also by inefficient management of this resource. Currently, the spectrum is statically allocated to licensed users even though some of them use this resource intermittently. This has resulted in underutilisation of the spectrum and therefore, spectrum scarcity for new users. Cognitive radio aims at solving this problem through dynamic spectrum access, which uses spectrum holes opportunistically. A cognitive radio can select the best channel available at a particular location and time. To accomplish that goal, the system requires some criteria, or channel quality estimation metrics, to rank the channels that it potentially could use. In this study, the authors present a survey on several channel quality estimation metrics such as bit error rate, signal‐to‐interference‐plus‐noise ratio, outage probability, channel quality estimation index, spectrum sensing accuracy of secondary user, and the idle state duration expectation.