| Abstract |
In this thesis, an amplify-and-forward cooperative single carrier-frequency domain equalizer (SC-FDE) system with the cognitive radio technology is proposed to improve the performance of the primary user and let the secondary user can transmit its information. To achieve this purpose, the data dependent superimposed training (DDST) scheme is employed. For the original DDST scheme, the data are transmitted in the time domain by SC-FDE and a part of the corresponding frequency-domain signal is discarded to insert pilots. In the proposed approach, after the secondary user receives the primary user’s data, it firstly amplifies the primary user’s data. Following, the DDST scheme is utilized to discard a part of subcarriers to insert the secondary user’s data. Finally, the overall signals are transmit to the primary user’s destination. At the primary user’s destination, it combines the signals from the primary user and the secondary user by maximizing the signal to noise ratio in the frequency domain. In addition, the signal to interference plus noise ratio and the bit error rate (BER) of the primary user is analyzed. Therefore, if the BER of the primary user is given, the number of subcarrier sharing to the secondary user is determined. From simulation results, the proposed approach is more suitable for spectrum sharing purpose than the cooperative orthogonal frequency division multiplexing system with the cognitive radio technology. |
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