Science & Engineering Research Support soCiety (SERSC)
In this paper, the authors present a dynamic spectrum access strategy to reduce the average overall system time of Secondary Users (SUs) in multi-channel cognitive radio networks. Before transmitting a packet, SU senses the spectrum environment. If there are free channels in the system, SU randomly selects one for transmitting. If all the channels are busy, they consider a probability-based spectrum selection scheme in which the access channel is chosen based on the predetermined probabilities for saving the sensing power and reducing the overall system time of SU. When the transmission of SU is preempted by the Primary User (PU), SU will stay on the operating channel and retransmit the whole data after PU leaves the channel.