Uplink Multiuser MIMO Detection Scheme with Reduced Computational Complexity

The wireless communication systems with multiple antennas have recently received significant attention due to their higher capacity and better immunity to fading channels as compared to single antenna systems. A fast antenna selection scheme has been introduced for the uplink multiuser multiple-input multiple-output (MIMO) detection to achieve diversity gains, but the computational complexity of the fast antenna selection scheme in multiuser systems is very high due to repetitive pseudo-inversion computations. In this paper, a new uplink multiuser detection scheme is proposed adopting a switch-and-examine combining (SEC) scheme and the Cholesky decomposition to solve the computational complexity problem. K users are considered that each users is equipped with two transmit antennas for Alamouti space-time block code (STBC) over wireless Rayleigh fading channels. Simulation results show that the computational complexity of the proposed scheme is much lower than the systems with exhaustive and fast antenna selection, while the proposed scheme does not experience the degradations of bit error rate (BER) performances

Investigation on the Tachyonic Neutrino

According to the experimental data, it is still controversial whether the neutrinos, especially the electron-neutrino and muon-neutrino, can be considered as the fermionic spinorial tachyons, and there is still no reliable report on the existence of the right-handed neutrinos. In this letter, we show that the neutrinos with the single handedness can not be the tachyons, but only those of the both handedness can be. Several implications of this result are discussed.Comment: 13 pages, latex, no figure