Cognitive radio performs efficient utilization of available communication resources. Cognitive ul... more Cognitive radio performs efficient utilization of available communication resources. Cognitive ultra wideband (UWB) system is a tempting candidate for short range and high data rate communication with low cost, and low power consumption. Wavelet packet based multicarrier modulation (WPMCM) UWB has inherent potential to fulfill cognitive radio requirements. In this research, we survey the literature on cognitive radio sensing mechanism in the presence of distortion and propose a novel link effect compensation accompanied by power loading, to mitigate the effects of interference from primary signal. Wavelet transform is used for spectrum sensing, and Lagrange multiplier applied for power allocation to minimize the bit error rate at the receiver. System performance is investigated by MATLAB to compare the system under different UWB channel models.
Cognitive radio has the ability to sense the environment and adapt its behavior to optimize commu... more Cognitive radio has the ability to sense the environment and adapt its behavior to optimize communication features, such as quality of service in the presence of interference and noise. In physical layer to achieve this goal, different phases of sensing, channel estimation, and configuration selection are necessary. The sensing part measures the interference level, recognize the spectrum holes, and send this information to channel estimator. In the next step, channel state information (CSI) is used for data detection and also sent to the transmitter through a limited feedback. CSI feedback consists of achievable rate, SNR value, modulation or coding schemes (MCS). Feedback link improves the system performance in the cost of complexity and delay. In this paper, we present and compare different feedback schemes for cognitive radio and study the channel capacity when an imperfect feedback link is corrupted by noise and delay.
Cognitive radio (CR) introduces the opportunistic usage of frequency bands and Orthogonal frequen... more Cognitive radio (CR) introduces the opportunistic usage of frequency bands and Orthogonal frequency division multiplexing (OFDM) is a strong candidate for CR design. Ultra wideband (UWB) radio fulfills some of the key cognitive radio requirements. Regarding the power limitations for UWB systems the main challenging issue is the impact of narrowband interference (NBI). Wavelet packet transform (WPT) is a possible choice for designing OFDM systems and has been shown as a solution to reduce interference. In this research, we explain the benefits of WPT from the literature, compare wavelet packet based MCM (WPMCM) for multiband UWB with its conventional version, and provide analytic schemes and block diagrams to implement proposed system.
Cognitive radio performs efficient utilization of available communication resources. Cognitive ul... more Cognitive radio performs efficient utilization of available communication resources. Cognitive ultra wideband (UWB) system is a tempting candidate for short range and high data rate communication with low cost, and low power consumption. Wavelet packet based multicarrier modulation (WPMCM) UWB has inherent potential to fulfill cognitive radio requirements. In this research, we survey the literature on cognitive radio sensing mechanism in the presence of distortion and propose a novel link effect compensation accompanied by power loading, to mitigate the effects of interference from primary signal. Wavelet transform is used for spectrum sensing, and Lagrange multiplier applied for power allocation to minimize the bit error rate at the receiver. System performance is investigated by MATLAB to compare the system under different UWB channel models.
Cognitive radio has the ability to sense the environment and adapt its behavior to optimize commu... more Cognitive radio has the ability to sense the environment and adapt its behavior to optimize communication features, such as quality of service in the presence of interference and noise. In physical layer to achieve this goal, different phases of sensing, channel estimation, and configuration selection are necessary. The sensing part measures the interference level, recognize the spectrum holes, and send this information to channel estimator. In the next step, channel state information (CSI) is used for data detection and also sent to the transmitter through a limited feedback. CSI feedback consists of achievable rate, SNR value, modulation or coding schemes (MCS). Feedback link improves the system performance in the cost of complexity and delay. In this paper, we present and compare different feedback schemes for cognitive radio and study the channel capacity when an imperfect feedback link is corrupted by noise and delay.
Cognitive radio (CR) introduces the opportunistic usage of frequency bands and Orthogonal frequen... more Cognitive radio (CR) introduces the opportunistic usage of frequency bands and Orthogonal frequency division multiplexing (OFDM) is a strong candidate for CR design. Ultra wideband (UWB) radio fulfills some of the key cognitive radio requirements. Regarding the power limitations for UWB systems the main challenging issue is the impact of narrowband interference (NBI). Wavelet packet transform (WPT) is a possible choice for designing OFDM systems and has been shown as a solution to reduce interference. In this research, we explain the benefits of WPT from the literature, compare wavelet packet based MCM (WPMCM) for multiband UWB with its conventional version, and provide analytic schemes and block diagrams to implement proposed system.
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Papers by Haleh Hosseini