2 METHOD FOR TRANSMITTING AND RECEIVING OF SECONDARY USER IN COGNITIVE RADIO NETWORK

摘要

In the wireless network, the transmitter of the secondary user checks whether the primary user is using the frequency band. Then, the primary user selects one of the overlay mode and the underlay mode according to whether the frequency band is used, do. The transmitter of the secondary user determines the transmission power in the selected mode and transmits the packet to the receiver of the secondary user at the determined transmission power. When the receiver of the secondary user fails to receive the packet, the transmitter of the secondary user or the secondary The user's repeater retransmits the packet.