Lu Weidang

Sensing time optimization in energy-harvesting cognitive radio with interference rate control

In this paper, an energy-harvesting cognitive radio (CR) is considered, which allows the transmitter of the secondary user (SU) to harvest the primary signal energy from the transmitter of the primary user (PU) when the presence of the PU is detected. Then the harvested energy is converted into the electrical power to supply the transmission of the SU at the detected absence of the PU. By adopting the periodic spectrum sensing, the average total transmission rate of the SU is maximized through optimizing the sensing time, subject to the constraints of the probabilities of false alarm and detection, the harvested energy and the interference rate control. The simulation results show that there deed exists an optimal sensing time that maximizes the transmission rate, and the maximum transmission rate of the energy-harvesting CR can better approach to that of the traditional CR with the increasing of the detection probability.

Global forward-predicting dynamic routing for traffic concurrency space stereo multi-layer scale-free network*

Many real communication networks, such as oceanic monitoring network and land environment observation network, can be described as space stereo multi-layer structure, and the traffic in these networks is concurrent. Understanding how traffic dynamics depend on these real communication networks and finding an effective routing strategy that can fit the circumstance of traffic concurrency and enhance the network performance are necessary. In this light, we propose a traffic model for space stereo multi-layer complex network and introduce two kinds of global forward-predicting dynamic routing strategies, global forward-predicting hybrid minimum queue (HMQ) routing strategy and global forward-predicting hybrid minimum degree and queue (HMDQ) routing strategy, for traffic concurrency space stereo multi-layer scale-free networks. By applying forward-predicting strategy, the proposed routing strategies achieve better performances in traffic concurrency space stereo multi-layer scale-free networks. Compared with the efficient routing strategy and global dynamic routing strategy, HMDQ and HMQ routing strategies can optimize the traffic distribution, alleviate the number of congested packets effectively and reach much higher network capacity.

Optimal time and bandwidth allocation based on Nash bargaining solution for cooperative cognitive systems

In this paper, we propose a cooperative spectrum sharing strategy based on the Nash bargaining solution. Specifically, the primary system leases a fraction of its transmission time to the secondary system in exchange for cooperation to improve its transmission performance. To gain access to the spectrum of the primary system, the secondary system needs to split a fraction of its transmission bandwidth to help to forward the primary signal. As a reward, the secondary system can use the remaining bandwidth to transmit its own signal. We find a unique solution for this time and bandwidth allocation using the Nash bargaining solution. Simulation results demonstrate that the performance of the primary and secondary systems can both be improved by the proposed spectrum sharing strategy.

Evaluation and improvement of LCR-DSR channel parameter estimator in mobile communications

Evaluation and improvement of LCR-DSR channel parameter estimator in mobile communicationsThis paper presents a comprehensive investigation on the optimization of a joint estimator employing the double sampling rate (DSR) technique, in which the Doppler shift estimation based on the level crossing rate (LCR) has been evaluated analytically in terms of the mean square error (MSE). Subsequently, the relationship between the MSE and the channel sampling interval is presented for optimization. Finally, the optimal channel sampling interval is obtained as well as an improved performance of the signal-to-noise ratio (SNR) and Doppler shift estimation. Sufficient simulations demonstrate a good performance for the proposed algorithm.

A novel covert communication system based on symmetric

A novel structure for covert communication is proposed in this study. The correlation coefficient of two adjacent symmetric

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Parameter estimator based on the log-cumulant and its performance analysis for heavy-tailed-distributed impulsive interference}{Parameter estimator based on the log-cumulant and its performance analysis for heavy-tailed-distributed impulsive interference

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Performance analysis of stochastic process modulation system based on autoregressive model under low SNR

S) noise sequences is modulated by the binary message sequence to achieve a covert communication system. In order to reduce the correlation of the modulated signal in the time domain, the modulated signal is scrambled by an interleaver. To verify the covertness of the proposed communication system, an improved circulation spectral density function is employed to detect whether the transmitted signal exists. The simulation results show that the proposed system has strong concealment. Moreover, the bit error rate (BER) performance is simulated and analyzed. The results show that the system has a good performance.

Anti-interference frequency spectrum access method based on full duplex OFDM cooperation

The impulsive interference in many wireless communication networks can be modeled as a symmetric