Control Signal Transmission Based on IFDMA and Receiver with Nonlinear Amplifier for Compensating Access Channel Mismatch

Dynamic spectrum access of cognitive radio exploits the low active channel and thus achieves the high frequency spectrum usage efficiency. Since it has freedom for access channel, the access channel of a node is different from that of the other one. It is an access channel mismatch. For compensating it, the exchanging of control signal between two nodes is required but the large delay and the low spectrum efficiency are serious problem. This paper proposes novel control signal and novel receiver for compensating access channel mismatch. In the receiver, we use nonlinear amplifier and thus the wide spread spectrum of distorted control signal can be detected even under the access channel mismatch. We use an interleaved frequency division multiple access (IFDMA) modulation scheme as control signal. IFDMA modulation has robustness to nonlinear distortion. Therefore, the peculiar feature of IFDMA modulation is used as identifying the control signal from detecting the spectrum of distorted IFDMA signal. The computer simulation shows that the highly accurate detection of control signal is achieved under the access channel mismatch and it is possible to inform the access channel number to the other node.