Abstract The multi-input multi-output with orthogonal frequency division multiplexing (MIMO-OFDM) is developed in order to improve data rate without any additional bandwidth. Many detection schemes have been developed in MIMOOFDM systems. Among detection algorithms, QR decomposition with M algorithm (QRD-M) has excellent error performance. However, the QRD-M has high complexity. In order to reduce the complexity, the low complexity QRD-M detection scheme is proposed in... The multi-input multi-output with orthogonal frequency division multiplexing (MIMO-OFDM) is developed in order to improve data rate without any additional bandwidth. Many detection schemes have been developed in MIMOOFDM systems. Among detection algorithms, QR decomposition with M algorithm (QRD-M) has excellent error performance. However, the QRD-M has high complexity. In order to reduce the complexity, the low complexity QRD-M detection scheme is proposed in this paper. The proposed scheme has the threshold in order to reduce tree search. Simulation results show that the proposed scheme has similar error performance with the conventional QRD-M and has lower complexity than the conventional QRD-M. Read More Read Less

Abstract In order to overcome the defect of particle swarm optimization(PSO) that it is easy to be trapped in local optimum, this paper presented a hybrid-advanced strategy, which combined the dual fitness method, dynamic neighborhood operator and randomly dynamically adjusting inertia weight convergence of particles. This calculation example showed that this advanced strategy could increase the local convergence ability and accelerate the... In order to overcome the defect of particle swarm optimization(PSO) that it is easy to be trapped in local optimum, this paper presented a hybrid-advanced strategy, which combined the dual fitness method, dynamic neighborhood operator and randomly dynamically adjusting inertia weight convergence of particles. This calculation example showed that this advanced strategy could increase the local convergence ability and accelerate the convergence of particles. Thus it was a simple and effective approach to solve nonlinear programming problems with complex and constraint conditions. This paper discussed the correlative issues in optimal scheduling of the cascade hydropower station and established a longterm optimal scheduling mathematics model of the cascade hydropower station based on the consideration of the electricity price in wet and dry season. Besides, it sought the solution by the application of improved PSO algorithm. The actual calculation results from the cascade hydropower station show that this model can help coordinate power generation and water consumption, and decrease profitless spill water of cascade hydropower station. This model can not only keep up a balanced power output in the dry season, but meet the need of flood mitigation and water storage in wet season, which is beneficial to a stable operation of the power system. The advanced PSO algorithm is a simple and effective approach to longterm optimal scheduling of cascade hydropower station based on the strength of quick calculation and precise convergence. Read More Read Less

Abstract In wireless communication system, the error performance is important when destination user is located in edge of base station cell coverage. It is difficult to improve the performance because the attenuation of the signal increases when the distance increases between destination user and base station. The proposed transmission scheme improves the bit error rate (BER) performance on the cell edge.... In wireless communication system, the error performance is important when destination user is located in edge of base station cell coverage. It is difficult to improve the performance because the attenuation of the signal increases when the distance increases between destination user and base station. The proposed transmission scheme improves the bit error rate (BER) performance on the cell edge. In the proposed transmission scheme, the cellular base station (CBS) is selected depending on the channel state and the transmit symbols are modified as space-time block code (STBC) symbol structure. Therefore, the proposed transmission scheme can be reliable in edge of basestation. Read More Read Less