Optimal Transmission Strategy without Capacity Loss at a Primary User in Cognitive Radio Networks over Inter-Symbol Interference Channels

In this letter, we consider a cognitive radio (CR) communication over inter-symbol interference channels. We propose a transmission strategy for a secondary sender to amplify the received signal from a primary sender and to transmit it together with its own signal by using characteristics of ISI channels. It is shown that the proposed strategy makes it possible for the secondary network to achieve considerable throughput without causing any capacity loss at the primary network, and it outperforms the conventional CR scheme.