多中继通信系统中量化误差补偿的MMSE中继预编码方案

为了补偿量化误差造成的系统性能的降级,文中提出将Grassmannian码本量化误差的统计特性引入多中继系统有限反馈中继预编码的设计,首先在QoS要求下的完全反馈中继预编码与接收均衡MMSE两步优化算法的基础上,给出了有限反馈下量化误差补偿的中继预编码与接收均衡MMSE两步优化方案,进而文中在中继和功率约束下,提出了一种有限反馈下量化误差补偿的中继预编码与接收均衡MMSE联合优化方案,并给出了中继预编码矩阵设计的闭合表达式.计算机仿真表明,文中提出的中继和功率约束下量化误差补偿的MMSE联合优化方案的系统性能优于QoS要求下量化误差补偿的MMSE两步优化方案,而且相比没有采用量化误差补偿的MMSE联合优化方案可以获得更低的误码率性能.     

基于误差修正的MIMO信道半盲估计方法

近年来，由于多输入多输出（MIMO）通信系统有传输速率高等许多优点，受到人们的重视。在本文中，提出了一种MIMO信道估计的方法，利用了已知训练序列和全部的数据帧信息，通过估计值的误差对信道参数作进一步的调整，只需使用较短的训练序列即可避免陷入局部最小，从而提高了信息传输速率和信道估计的鲁棒性，提高了估计的精度，而且具有较低的计算复杂度。     

Combined adaptive beamforming with space-time block coding for multi-antenna communications

Aiming at the multi-antenna communication systems, a downlink transmit scheme combining adaptive beamforming （ABF） with space-time block coding （STBC） is first presented, which utilizes the maximization of the output mean signal-to-noise ratio （SNR） and the minimization of the symbol error rate （SER） upper bound of the three widely used modulations as the design criteria. Then, based on the moment generating function （MGF） and the Gauss-Chebyshev integration, a simple and accurate numerical method is presented to analyze the SER performance of the system with the new transmit scheme under the three commonly used modulations. Finally, computer simulation results demonstrate the effectiveness and superiority of the proposed strategy.     

The Study of Chaotic Neural Network and its Applications in Associative Memory

Based on an analysis of current principal chaotic neural network models and their applications in information processing, we propose a one-dimensional, two-way coupled map network and a modified definition of an auto-associative matrix. The two-way coupled map network overcomes the weakness of the globally coupled map network and has the same abilities in pattern classification. Numerical simulation experiments have shown that the associative success rate and recall speed of our modified definition of the auto-associative matrix are an improvement them over existing methods. Moreover, the associative recall process of the network is analyzed in detail and explanations of improvement are given, basd on our theoretical analysis.     

Transmission scheme and performance analysis for decode-and-forward MIMO two-way relay systems

In decode-and-forward (DF) MIMO two-way relay systems, the transmission schemes are designed and the closed-form expressions for the outage probability and average symbol error rate (ASER) of the twoway relay system are derived based on two different scenarios of channel state information (CSI). For perfect CSI, the maximum-ratio-transmission and combining (MRT-MRC) technique is applied to design the beamforming and combining vectors. Without perfect CSI, the transmission scheme with limited feedback is designed, and the analytical results are verified through two kinds of codebooks, i.e., random vector quantization and Grassmann. The simulation results show that, the proposed transmission schemes for the two-way relay system can outperform other transmission schemes in the performance of outage probability and ASER, and the accuracy of the derived closed-form expressions is also verified by the numerical simulations.