Meng Li-min

An Adaptive Doppler Shift Estimator in Mobile Communication Systems

In this paper, an adaptive Doppler shift estimator based on the square envelope autocorrelation function of the mobile propagation channel is proposed. Furthermore, the proposed estimator exploits the iterative minimum finding procedure to reduce the effect of additive noise. Both the theoretical analysis and the experiments are provided to show that the proposed method yields fairly good signal-to-noise ratio (SNR) insensitive performance in a wide range of velocities and SNRs

Routing protocol based on Grover's searching algorithm for Mobile Ad-hoc Networks

In Mobile Ad-hoc Networks (MANETs), routing protocols directly affect various indices of network Quality of Service (QoS), so they play an important role in network performance. To address the drawbacks associated with traditional routing protocols in MANETs, such as poor anti-fading performance and slow convergence rate, for basic Dynamic Source Routing (DSR), we propose a new routing model based on Grovers searching algorithm. With this new routing model, each node maintains a node vector function, and all the nodes can obtain a node probability vector using Grovers algorithm, and then select an optimal routing according to node probability. Simulation results show that compared with DSR, this new routing protocol can effectively extend the network lifetime, as well as reduce the network delay and the number of routing hops. It can also significantly improve the anti-jamming capability of the network.

An improved method for Doppler shift estimation in CP-SCBT Mobile Communication Systems

In this paper, the Doppler shift of the time-varying multi-path channel is estimated by calculating the expectation of the ACF (auto-correlation function) of the channel coefficient estimates on the effective fingers. Furthermore we analyze the estimation bias and propose an improved estimation method based on SNR (signal-to-noise ratio) estimation to obtain the high estimation accuracy in wide ranges of velocities and SNRs.

Relative Entropy of Entanglement of a Kind of Two-Qubit Entangled States

We in this paper strictly prove that some block diagonalizable two qubit entangled state with six none zero elements reaches its quantum relative entropy entanglement by the a separable state having the same matrix structure. The entangled state comprises local filtering result state as a special case. PACS: 03.67.Mn;03.65.UdWe strictly prove that some block diagonalizable two-qubit entangled state with six non-zero elements reaches its quantum relative entropy entanglement by a separable state having the same matrix structure. The entangled state comprises local filtering result state as a special case.

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.

Research on routing model for MANET based on quantum search algorithm

Ad Hoc networks is recently a hot spot in wireless network researching domain. The design of routing algorithm, which is as the core layer technology in Ad Hoc networks, has drawn great concern. In response to the drawbacks of traditional routing protocols such as bad convergence and providing no QoS guarantee, this paper gives the way to construct node vector function to represent QoS indices in networks. And then combining the idea of Grover quantum searching and DSR protocol, it puts forward a MANET routing model based on Quantum search algorithm. In the process of routing, this algorithm gets node probability vector by Grover computation on node vector function in networks. Results of simulation show that comparing with DSR protocol, routing algorithm based on Quantum search algorithm can converge quickly and provide QoS guarantee, which fills up the deficiency of the exiting algorithm.

Research on routing algorithm for MANET based on Grover searching theory

This paper puts forward a routing algorithm based on Grover searching theory for MANET. It first gives the Grover searching theory and the construction way of probability branch matrix and solution path matrix which are suitable for MANET. And then, on this basis, define probability computation equation to compute each nodes probability. Select nodes with high probability to transmit datagram to reduce computation quantity in networks and make the routing converge quickly.