1. A dynamic frequency allocation device for allocating a dynamic frequency for a secondary user in a cognitive radio network, the dynamic frequency allocation device comprising:an OP map generation unit configured to generate an OP (opportunity) map by using one or more of spectrum sensing information, an access request message, and a density and a transmission power of primary transmitters, the spectrum sensing information comprising identifier information, location information, and a sensing measurement matrix and received from a spectrum sensor which has completed sensing, the access request message comprising identifier information, location information, and operable band information and received from a secondary transmitter wishing to acquire a frequency access opportunity, the OP map representing a probability of successful communication of the secondary transmitter in each region of the cognitive radio network; and
a response message generation unit configured to generate a response message based on the generated map, the response message comprising a channel having a highest probability of successful communication from among channels accessible from a location of the secondary transmitter and the probability of successful communication,
wherein the probability of successful communication is a probability of a SINK (signal-to-interference-plus-noise ratio) at a particular location exceeding a predefined reference value ?*,
and the OP map representing the probability of successful communication in each region comprises the probability of successful communication of the secondary transmitter in a region in which the spectrum sensor is not installed.